Cancer: Definition, Symptoms, Risk Factors, and Treatment

Overview of Cancer

Cancer is a group of diseases that develop due to the transformation of normal cells that, causes the cells to multiply rapidly and spread to other body parts. It is the most important cause of death in the UK, with 248 annual deaths per 100,000 population in 2021 and ranking above cardiovascular diseases and COVID-19 (GOV.UK). Cancer is hazardous, and it is impossible to cure some cancers completely. However, early diagnosis and treatment help people live longer and better lives. The research is ongoing to understand the mechanisms of cancer, the role of various risk factors and novel treatment options. The information about the growth and proliferation of cells is encoded in the genes. The body has many barriers to controlling the division of cells. Even the death of cells (apoptosis) is planned to ensure that the worn-out and non-functional cells are replaced rapidly. The cancerous cells overcome all such barriers and grow out of control. They break the cellular adhesions and reach other body parts through the bloodstream or lymphatic system. 

The cancers are categorised according to the name of the organ where they develop, like lung cancer, stomach cancer, breast cancer, colorectal cancer, blood cancers or prostate cancer or according to their spreading ability, like benign cancers that do not spread to the other body parts and malignant cancers that spread rapidly. Various causes and risk factors of cancers are genetic factors, exposure to radiation and chemicals and lifestyle risk factors like smoking, pollution, unhealthy diet, poor lifestyle, exposure to UV light, heavy alcohol consumption, age and some viral infections. There are various symptoms of cancer like fatigue, unexplained weight loss, persistent pain, difficulty in swallowing and breathing, changes in senses like hearing and vision, headaches and constant dizziness, unexplained discharges and bleeding, continuous coughing, the development of lumps in different body parts and changes in skin colour. 

However, the doctor uses more advanced diagnostic options and tests like cytogenetic analysis, imaging techniques, sputum cytology, rumour marker tests, urinalysis, blood chemical profile, organ biopsies, liquid biopsy, immunophenotyping, complete blood count, etc. Cancer is categorised into various stages depending on the nature and spread of lesions, and each stage needs separate care and management. The main treatment options for Cancer therapy are chemotherapy, hormone therapy, radiotherapy, photodynamic therapy, stem cell therapy, surgeries etc. 

 

What is cancer? 

Cancer is abnormal cell growth that often originates from a single abnormal cell. The loss of control mechanisms on cell growth causes the cells to multiply rapidly, invade the adjacent tissues and spread to the other body parts. There is the growth of new blood vessels that supply the essential nutrients to the proliferating cells. The development and multiplication of cancer cells create a solid mass consisting of cancerous cells called the tumour. The cancer destroys the structural and functional integrity of the adjacent cells and tissues. Metastasis refers to the spread of cancerous cells from the original development site to the other sites.

 

How common is cancer?

The cancer continued to be the primary cause of death worldwide and throughout history. The improvements in the treatment and management of cancers have resulted in lower incidence rates in the past years. 

The risk of cancer varies by age, gender and exposure to the risk factors. In the United Kingdom, 387,820 cases of all types of cancers were reported in 2019. Men's case number was slightly higher (200,386) than women's (187,434). Compared to the data in 2017, there was a 7.2% increase in cancer cases in men and a 4% increase in women (UK Cancer Statistics, World Cancer Research Fund). 

In the same year, 166,502 cancer-related deaths were reported in the UK. Most of the deaths (88,688) were in men, and 77,814 were reported in women. The figures amount to 450 cancer deaths daily. The most common cancers in the country, in the order of fatalities, are breast cancer, prostate cancer, lung cancer, bowel cancer, skin cancer, non-Hodgkin's lymphoma, head and neck cancer, kidney cancer, bladder cancer, uterine cancer, leukaemia, oesophageal cancer, myeloma and ovarian cancer. 

In the children, an average of 1,832 new cancer cases was reported annually between 2016-18, with 253 annual deaths (CancerresearchUK.org). The instances in children represent less than 1% of all cancer cases, and the rate is highest in the under-5 children. The incidence rate of cancer increases with age, and the peak rate is observed in people 85-89 years of age. Likewise, more than one-third (36%) of all cancer cases are reported in people 75 or above. A steep rise in the incidence rate of cancers is observed after age 55-59.

 

How is Cancer Developed?

Both the birth and death of cells are planned, and the genes in the DNA guide the cells. The mutations in these genes due to exposure to various risk factors, like advanced age, exposure to ultraviolet radiation and different cancer-causing chemicals, control over the division and death of the cells is lost. As a result, the cells start dividing uncontrollably, and a mass of cells (tumour) develops. The canner cells are different from the normal cells in that they are immature, do not differentiate into more specialised cells, evade the immune mechanisms that cause the cell death, ignore the death signals produced by the body and don't stick to their sites and spread to various other tissues and organs and destroy them.

The blood vessels develop (angiogenesis) in the tumour, which supplies essential nutrients to the cancer cells, and the cells continue to multiply. As the tumour mass grows, some cells become capable of breaking the cellular adhesions and start spreading to the other sites in a process called metastasis. 

Not all types of cell division and growth are cancerous, and there are some non-cancerous conditions like hyperplasia in which there is a faster multiplication of the cells, but the cells are normal and are organised like normal cells, dysplasia in which case there is an excessive build-up of normal cells but different in the structural organisation from the normal cells and carcinoma in situ where the abnormal and cancerous cells are present, but, they do not invade the normal tissues. Carcinoma in situ is often called stage 0 cancer and is treated many times; it advances to the following stages.

 

What are the types of cancer?

More than 200 types of cancers are classified based on different criteria like the organ of origin like lung cancer, breast cancer etc. and the nature of the tissues involved like carcinoma, sarcoma, lymphoma, myeloma etc. While naming cancers according to the organs involved is easy, the classification based on the tissues involved is worth understanding. Five major groups of cancers on that basis are;

Carcinomas: These cancers develop in the skin or the epithelium, i.e., the lining of internal organs and body cavities like the abdominal and chest. Carcinomas are by far the most abundant types of cancer and account for more than 85% of all cancer cases in the UK. There are different types of carcinomas based on the type of epithelium tissues. These include squamous cell carcinoma, which develops from the squamous cells, which are the flat cells that cover the skin and the linings of food pipe and throat; adenocarcinomas, which originate from the epithelial cells that produce different secretions; transitional cells carcinoma, which develop from transitional cells that line the stretchable organs like bladder and uterus and the basal cell carcinoma that originates from the basal cells that are located in the deepest layers of skin. 

Sarcomas: These cancers develop in the connective tissues like bone, soft tissues, tendons, cartilage and fibrous tissues. They are significantly fewer and make up less than 1% of all diagnosed cancer cases. Depending upon the soft tissues involved, the sarcomas are named bone sarcoma, which develops from the bone tissue; chondrosarcoma, which originates from the cartilage; and myosarcoma, which develops from the muscle cells. 

Leukaemia: The term leukaemia is used for all blood-related cancers. They develop from the abnormal growth of the white blood cells in the bone marrow. The bone marrow produces different types of white blood cells, so there are various leukaemias. Leukaemias are very common in children but form only 3% of all cancer cases in the UK. 

Lymphomas: Lymphomas are cancers that originate from the lymphatic system. The lymphatic system is present all over the body, so lymphomas are able to develop anywhere in the body. The lymphatic system's lymphocytes (white blood cells) start dividing oddly and do not die when needed. There are numerous immature lymphocytes in the circulation. Both of these factors reduce their ability to fight infections. The cancerous lymphocytes gather to form tumours in the lymph nodes or the tissues like the spleen and bone marrow. Lymphomas are pretty common and are 5% of all cancer cases in the UK.  

Myeloma: It is cancer that develops from the plasma cells, a type of white blood cells that are produced in the bone marrow. These cells produce antibodies as a part of the immune response to fight infections. The cancerous plasma cells start dividing uncomfortably and produce dysfunctional antibodies. Myelomas are rare and around 1% of all cancer cases in the UK. 

Tumours of the spinal cord and brain: The brain and spinal cord are made of billions of cells called neurons, forming the central nervous system. The nerves coming out of them constitute the peripheral nervous system. The brain has a supportive tissue made of glial cells that support the cells of the nervous system. Most brain tumours called gliomas develop from these glial cells. Some other tumours form in the brain or the Spinal cord that are both benign and malignant. The tumours originating from the brain and spinal cord make up 3% of all cancer cases in the UK. 

 

What is the cause of cancer?

Cancer has no single cause, and it is established that a complex interaction of factors like genetics, individual characteristics and environmental factors combine to cause cancer. Genes are the parts of chromosomes and DNA that control a specific function in the body. These genes undergo mutations, i.e., changes due to lifestyle choices, diet and exposure to carcinogen radiations and chemicals and become cancerous. The mutations in the genes are often inherited. An example of such transformation is the Lynch syndrome due to the inability of DNA to repair the damages and cause uterine and colon cancers at an early age. 

Another example is the mutations in the BRCA gene family that cause an increased risk of ovarian and breast cancer. Several lifestyle factors and choices increase the risk of mutations like tobacco smoke, exposure to ultraviolet radiation, use of processed foods, excessive alcoholism, viral infections, obesity and chronic inflammations like ulcerative colitis. Some environmental factors increase the risk of cancers like chemicals, e.g., Benzene, asbestos and talcum powder, exposure to ionising radiations like x-rays, exposure to chemical carcinogens and high doses of chemotherapeutic drugs and the use of immune suppressive and hormonal drugs. 

There are various infectious causes of cancers, including human papillomavirus (HPV), Epstein Barr virus (EBV), hepatitis B and C viruses, Merkel cell polyomavirus, human T-lymphotropic virus and the bacteria like Helicobacter pylori. Some of these viruses, like HPV, spread through sexual routes.  The type of cancer and the nature of the causative agent influence the treatment strategy.

 

What are the Symptoms of Cancer?

There are hundreds of different types of cancers, and each type causes different signs and symptoms depending on the organs and systems involved. These symptoms range from organ and site-specific symptoms like the development of localized tumours to more generalised symptoms like unexplained weight loss, tiredness, pain etc. All people do not experience the same type of signs. Here is a list of symptoms most commonly associated with the tumour. 

1. Unexplained weight loss: Weight Loss and gain are often experienced in most health issues like ageing, pregnancy, menopause etc. However, losing excessive weight (10 pounds or more) rapidly without any known cause is a sign of cancer.
2. Fatigue: Fatigue is the body’s physical response to various issues like stressful life events or troubled sleep. But, feeling tired all the time without any known cause is often a sign of cancer, and the patient must visit the doctor.
3. Persistent pain: Pain is a mechanism used by the body to express negative issues in the body. The aches and pains are widespread with the advancing age. However, persistent and regular pains in the body without any known cause are often due to more severe issues like cancers.
4. Swelling problems or changes in the bowel: The cancers in the throat, mouth or oesophagus interfere with swallowing and make it disturbing and painful. Likewise, some issues with the faeces, like faecal inconsistency, bowel leakage and blood and mucus in the faeces for a long time, are sometimes due to cancerous growths.
5. Changes in vision or hearing: Vision changes occur in eye cancer, causing the images to become blurry. Some other signs are wiggly lines, light flashes and shadows in the vision. Occasionally, a dark patch develops in the eyes that continue to grow. Similarly, changes in hearing are noted in some neck and head cancers. Anticancer treatments like radiotherapy and chemotherapy often cause damage to vision and hearing. 
6. Constant dizziness and headaches:  Dizziness and lightheadedness for many days that don't respond to treatments are often signs of brain and spinal cord tumours. Both primary and metastatic brain tumours cause these signs. 
7. Unexpected bleeding or discharge: Vaginal bleeding and discharge are observed in the vaginal, cervical, uterine, tubal and ovarian cancers. Similar signs are reported when cancers develop close to the body's natural orifices, like the throat, mouth, anus, intestines, etc. 
8. Continuous coughing: A persistent and non-responsive cough is among the first signs of cancer in the lungs and other respiratory organs. Almost 57% of patients diagnosed with lung cancer experienced chronic cough as the first sign (Alex Molassiotis and colleagues, NIH)
9. Development of lumps: The uncontrolled growth of cancer cells leads to the development of large lumps of poorly differentiated cells. In the case of metastatic cancers, the lumps mainly develop in the lymph nodes. The Lumps forming inside the body are detected only during testing, but those growing on the skin, lymph nodes and breasts are palpable by hand.
10. Changes in skin colour: During the final stages of cancer, the body cannot regulate blood flow and temperature, causing the skin to take a bluish tinge. The skin sometimes becomes mottled. Sometimes, the skin becomes oversensitive to light and develops sunburns quickly on exposure to sunlight. Skin pigmentation and depigmentation are often noted. Skin colour changes are essential findings of melanoma (skin cancer).

 

Unexplained weight loss

Unexplained weight loss is weight loss that is not due to any apparent cause. It is common in people with cancer and is often the first sign of disease. Around 40% of people diagnosed with cancer reported that they experienced weight loss before their first time being diagnosed with cancer. Losing 10 pounds or 5% of the body weight within 6 months or less without any known cause must be taken seriously and consulted with a doctor. The weight loss in cancer is different from other types and is characterised by poor quality of life, loss of skeletal muscles, poor appetite, fatigue and a higher rate of metabolism. Oncologists use the term cachexia for the chronic wasting experienced in cancer and other chronic diseases. 

The development of cancer and anticancer treatments causes the loss of appetite. As the growing tumours need nutrients, the body starts breaking down its fats and muscles to fulfil the rising demand. Some other signs associated with certain cancers cause weight loss like vomiting and nausea, depression, pain, loss of taste, difficulty swallowing and chewing, mouth sores, diarrhoea and constipation. Bowel cancers cause persistent diarrhoea and constipation due to the growth of tumours and the resultant inflammatory responses, which lead to persistent weight loss due to poor absorption of nutrients from the intestines. 

 

Fatigue

Cancer fatigue means the inability to perform regular activities and feelings of exhaustion. Such fatigue doesn't go with sleep or rest and is due to negative changes inside the body. It is among the most common side effects of cancers and anticancer treatments. The fatigue experienced during cancer is very severe and is often described as paralysing by the patients. It is reported by most 40-100% of cancer patients (Boris Zaydiner, PhD). 

Besides the physical causes, it is related to the stress of having a life-threatening disease that is likely to end the life in a few years. Various other causes linked to cancer-related fatigue are inflammation, dehydration, cell and tissue damage, loss of functions of blood cells (in leukaemia) etc. Anticancer treatments like chemotherapy, radiotherapy, immunotherapy, biological therapy, bone marrow transplant and various complications like insomnia, pain, hypothyroidism, poor nutrition, anaemia etc., are linked to extreme fatigue.

Persistent pain

Pain is a generalised or localised unpleasant sensation that causes some emotional and physical discomfort and reflects pathological events in the body. Cancer pain is of different types and has many other causes. Most of the time, the cancer pain is due to the pressing of organs, nerves and bones by rapidly growing tumours. Some cancer treatments like chemotherapeutic drugs cause tingling and numbness in the feet and hands and burning pain at the injection site. Likewise, radiotherapy causes irritation and redness of the skin. The cancer pain is primarily chronic and is mediated by various chemicals, e.g., cytokines released by the tumour, and it often stays long after the anticancer treatment. 

Depending upon the tissues involved, cancer pain is of different types like neuropathic pain, which causes a feeling of crawling or tingling under the skin; very dull, throbbing and aching bone pain; soft tissue pain (or visceral pain), causing sharp throbbing, aching and cramping; phantom pain, which develops in the area where some tissues have been removed like pain in the breast area after breast surgery and refereed pain that is due to issues in some organs but develops in other parts of the body, like liver inflammation cause the pain in the right shoulder. The nature and severity of the canner pain depend upon the type, location and stage of the tumour and the treatment options used, such as surgeries.

Swelling problems or changes in bowel

Bowel changes occur due to the involvement of the intestines during colon or rectal cancers (colorectal cancers). Various symptoms associated with colorectal cancer are pain in the bowel and abdominal region and abdominal cramps, distension and bloating. Some changes in the bowel habits are indicative of bowel cancer. These include diarrhoea, constipation, changes in the calibre, size and frequency of bowel movements, improper bowel emptying and narrow stools. The other signs are rectal bleeding and blood in the stools etc. These bowel changes occur during some other conditions like dietary modifications, bacterial and viral infections and diseases like haemorrhoids. However, persistent signs must be reported to the doctor. 

Swelling or oedema is a sign of inflammatory responses. Oedema refers to a situation in which excessive fluids accumulate in the tissues due to pathological issues like inflammation, certain cancers and the use of some anticancer drugs. Oedema and swelling due to anticancer drugs and other problems cause swellings in the legs, ankles and feet, arms, hands, abdomen and skin. The skin becomes puffy to the touch and becomes shiny and dented when gently pressed. These signs, without any established cause, reflect the possibility of cancer.

Changes in vision or hearing

The vision changes are observed in various eye cancers like squamous cell carcinoma, lymphoma, eye melanoma and eye retinoblastoma. The symptoms associated with eye cancer are blurred vision, the development of a dark patch in the eye that grows bigger and bigger, bulging of one or more eyes, partial or complete loss of vision, the development of a lump on the eye (s) that increases in size, the wiggly lines, shadows or light flashes in the vision and a rare but persistent pain in the eyes. However, These symptoms are not necessarily a sign of cancer and develop in other eye conditions, too, and 11% of cases of eye cancer do not cause any symptoms. The vision changes must be discussed with the doctor to determine the exact cause. 

Hearing issues develop after cancer treatment due to the side effects of treatment options. Some causes of hearing issues are chemotherapeutic drugs like carboplatin and cisplatin that damage the cochlea located in the inner ear and the damage to the inner ear due to radiation therapy, whose signs appear 2-3 weeks after the treatment and continue to worsen. The radiations cause the thickening of the ear wax and swollen eustachian tubes and lead to the buildup of fluids in the inner ear. High doses of radiation cause more permanent damage to the ears. Likewise, surgical procedures related to cancers and using medications like antibiotics (like streptomycin, tobramycin, gentamicin, neomycin and erythromycin) and diuretics (like furosemide) cause hearing problems. 

Constant dizziness and headaches

Dizziness is the presence of a whirling sensation in the head with the resultant tendency to fall. Both issues are experienced during cancer or in the aftermath of anticancer treatments. It causes a person to lose balance and feel as if the room is spinning, and the symptoms worsen during walking, standing up and climbing the stairs. Many factors causing dizziness during cancer are side effects of anticancer medications, anaemia which develops during the chemotherapy and radiography, tumours in the brain that influence the body balance and the use of radiation therapy for cancers in the brain and spinal cord. Headache and dizziness are expected during various other issues besides cancer, like stroke, high or low blood pressure, hypoglycemia, dehydration, inner ear infections and injuries, advanced age and a sudden rise or fall. Therefore, persistent headaches and dizziness must be reported to the doctor for diagnosis of the cause. 

Unexpected bleeding or discharge 

Usually, the blood stays in the blood vessels. When it comes out, the condition is called bleeding. Changes in the pattern of bleeding and discharge are the symptoms of cancers, particularly vaginal, cervical, uterine, tubal and ovarian cancers. Likewise, changes in the vaginal discharge, like longer and heavier periods, unusual bleeding in between the periods, and bleeding after sexual intercourse or after menopause, are experienced in the cancers of the reproductive tract. Changes in the discharge from the nipples and skin eruptions that ooze out foul-smelling discharge and swollen and lumpy breasts are observed in breast cancer. Usual bowel leakages and blood in stools are observed in bowel cancer. Any unusual discharge from anywhere on the body or from the body cavities is a sign of severe issues, including cancer.

 

Continuous coughing 

Coughing is the involuntary and sudden expulsion of air from the lungs with a short and sharp noise. A persistent and non-responsive cough is one of the earlier signs of cancer in the lungs and other respiratory organs, and 50% of people report experiencing cough at the earlier stages of lung cancer. The cough during lung cancer is either the result of stimulation of cough receptors by the tumour tissues or the inflammatory responses generated by the body that cause the stimulation of local nerves in the air passageways. 

Sometimes, pleural effusion (the build-up of fluids in the chest cavity) develops in lung cancer, which becomes a cause of cough. The cancer cough differs from the other types, and some features distinguish it from them. These include a chronic cough lasting more than 8 weeks, sleep disturbances, hemoptysis (coughing up blood), breath shortness, chest pain and the occasional development of pneumonia and bronchitis.

 

Development of lumps 

The lumps are irregular masses of poorly differentiated cells that develop due to the excessive proliferation of cancerous cells. The cancerous cells break away from the primary tumour and use the lymphatic system and blood to reach other distant locations and organs where additional secondary tumours are developed. The process is called metastasis. The lumps in the rapidly growing and dangerous (malignant) tumours form much faster than those of the benign tumours. Cancerous tumours develop anywhere in the body, and the significant development sites are the abdomen, shoulder, arms, pelvis, etc. The growth of multiple tumours means a poor prognosis (disease outcome) as the disease has already spread to various body parts. The cells in these lumps are poorly differentiated, have rapidly dividing capabilities and are invasive. 

 

Changes in skin colour 

Normal skin colour shows marked variations and ranges from pale white to dark brown and even black. So, there is nothing like a normal skin colour. The changes in skin colour reflect diseases, including cancer. Some people observe hyperpigmentation of the skin which means darkening of the skin due to the overproduction of black pigment melanin, which is produced by cancer of skin cells called melanocytes (melanoma). 

The skin colour changes are particularly prominent during and after the anticancer treatments. Such changes tend to resolve after the end of treatment. Some typical skin changes during the chemotherapy are peeling, darkening, redness, itchiness and dryness. Sometimes, minor or significant rashes develop due to photosensitivity. The skin becomes mottled and discoloured towards the end stages of cancer when essential functions like blood pressure and temperature regulation are compromised.

 

What is the Risk Factor of Cancer?

It is impossible to understand why some people develop cancers, and others do not. However, some risk factors increase cancer risk, and some protective factors decrease the risk. The risk and protective factors are identified by large-scale epidemiological studies where a large group of people is studied. These studies highlight the stakes in a population but do not cover the risks that individual persons within the population face. Here is a list of some common risk factors for cancer.

1. Age: Cancer risk increases with advancing age, and the rate becomes exceptionally high after age 60. The data published by the NCI's surveillance has noted that the median age for cancer diagnosis is 66 years. Half of the cases are diagnosed before age 66 and half after 66. 
2. Exposure to radiation: Some radiations are known as ionizing radiations because they cause cancer by damaging the DNA. The visible light is safe. However, some ionizing radiations known to cause cancer are gamma rays, x-rays and radon. 
3. Tobacco use: Different carcinogenic chemicals in tobacco smoke cause cancer and are among the leading causes of cancer-associated deaths. Tobacco is a risk factor for cancers of the lungs and many other organs. Both active and passive smokers are at risk, and there are no safe levels of use of tobacco and tobacco products.
4. Exposure to air pollution: Various pollutants in the outdoor air, like gaseous pollutants, particulate matter, metallic particles etc., cause a substantial increase in the risk of cancer. Recent research has found a link between the risk of different cancers and outdoor air pollutants.
5. Unhealthy diet: Some dietary components and nutrients are associated with an increased risk of cancer. Some nutrients, food additives and nutritional components associated with cancer are acrylamide, alcohol, antioxidants, artificial sweeteners, charred meat, calcium, fluoride, cruciferous vegetables, tea, vitamin D etc.
6. Lack of physical activity: Lack of physical activity causes obesity, a risk factor for many types of cancers, including breast, colorectal, endometrial, etc. Alternately, maintaining a healthy and active lifestyle and maintaining an ideal body weight (BMI) reduces the risk of cancers. 
7. High alcohol consumption: Excessive alcohol consumption increases the risk of liver, mouth, throat, larynx, oesophagus, and breast cancers. Some substances added to alcoholic beverages, such as preservatives and flavours, are associated with cancer risk.
8. Unprotected exposure to UV light: Ultraviolet radiation (UV light) is high energy and ionizing radiation, and too much-unprotected exposure to it causes damage to the DNA, causing dangerous mutations that result in cancer. Little exposure is relatively safe. However, little by little, enough genetic mutations build up to cause cancer. 
9. Certain virus infections: Different infectious agents, including viruses and bacteria, are associated with an increased risk of infections. Some viruses like HPV disrupt the death and multiplication signals that are very important to control the population of cells. Some other diseases (like HIV) pave the way for cancer by suppressing the immune system.

 

 Age

People of all ages experience cancers. However, ageing is a considerable risk factor. As a person ages, the growth potential of the cells decreases substantially, and the risk of genetic mutations increases. Over time, these mutations build up to cause an increased risk in the elderly. As a result, more than half of cancer cases are reported in people over 70. Besides the internal factors, various external factors like increased exposure to carcinogenic chemicals, cigarette smoke and radiation in older men cause more risk. The body fixes most of the damage caused by cancer-causing agents. However, in older people, the ability of the body to manage the damage is reduced. So, the damages build up over time. Given the high risk of cancer in older adults, more screening services are provided to the old age group to allow early detection of cancers for proper treatment and better survival.

 

Exposure to radiation 

A light source emits radiation, allowing us to see the objects around us. Visible light is essential for vision. However, invisible ionizing radiations, like x-rays, radon, gamma rays and alpha particles etc., cause damage to the cellular DNA by their ionizing effects. Over time, these mutations build up to cause an increased risk of cancer. People working at the sites, like nuclear reactors are provided extra safety equipment to protect them from radiation. 

Radon gas is produced by the radioactive matter (radium) in the soil and rocks. High-level exposure to it causes a higher risk of lung and other cancers. The Home radon testing kits are available at hardware stores and allow people to detect radon levels in their home soil to reduce it to safer levels. Likewise, neutrons, beta particles, alpha particles, gamma rays and x-rays are released into the atmosphere from accidental leakage from nuclear power plants and many natural sources. These radiations are used in some medical procedures like CT scans and chest X-rays, and excessive use of these techniques causes damage to the cells, causing cancers. However, a careful and experienced worker allows a safer and risk-free use. 

 

Tobacco use

Tobacco smoke is a source of many cancer-causing chemicals like aromatic amines, N-nitrosamines and polycyclic aromatic hydrocarbons (PAHs), inhaled by active and passive smokers exposed to second-hand smoke. There are more than 7000 chemicals in cigarette smoke; many are poisonous, and at least 70 are known carcinogens. As a result, regular smokers have a 15-30 times higher risk of developing cancer or dying from cancer-related complications than non-smokers.

These chemicals in tobacco smoke increase the risk of many types of cancers like cervical, colorectal, pancreatic, stomach, liver, kidney, bladder, throat, oesophagus, mouth, larynx, lungs and even blood cancers like myeloid leukaemia. No tobacco products are safe at any level, and people using nicotine-free vapes, snuffs and chewable tobacco products are exposed to a higher risk of cancers. People of all ages have an increased risk of cancers from tobacco. However, the risk is higher at an advanced age. Therefore, leaving tobacco products improves life expectancy for cancer patients.

 

Exposure to air pollution 

Air pollution means a higher level of indoor and outdoor air pollutants. Both are associated with a higher risk of cardiac, respiratory, and cancer. Air pollution is a mixture of different substances and dust-like particles. The most common air pollutants are carbon dioxide, carbon monoxide, particulate matter, smog, polycyclic aromatic hydrocarbons, oxides of nitrogen, ammonia, asbestos, formaldehyde, ground-level ozone, methane, benzene, lead, particulate matter and oxides of sulfur. The air pollutants originate from various natural sources like wind storms, dust storms, volcanic eruptions and forest fires and various artificial sources like smoke from burning fossil fuels and fumes from factories and vehicles. Outdoor air pollution accounts for 10% of cancer cases (CancerresearchUK.org).

The particles and gaseous pollutants in the air damage the DNA and increase the production of oxide free radicals that damage the cells and their DNA, causing genetic mutations. The damaged and mutated cells are naturally produced, but the body the immune system kills them. Various air pollutants cause the activation and survival of these cells and encourage their growth and proliferation. Besides the lung cancer, there is a high risk of other cancers like breast cancer. Various carcinogenic chemicals in the polluted air include dioxins, polycyclic aromatic hydrocarbons, formaldehyde, benzene, and many more. 

 

Unhealthy diet 

An unhealthy diet contains high levels of processed foods, chemical preservatives and other chemicals that cause damage to the body cells. Some high-energy, low fibre and high-fat foods increase the risk of obesity, a risk factor for many cancers. Using processed and preserved meats like burgers, sausages, bacon, ham, and hot dogs increase the risk of bowel cancer. The use of red meat is another risk factor for bowel cancer. Likewise, research is underway to understand the link between high fats in foods and cancer. 

Even if food is not a direct cause, it causes obesity, increasing the risk of endometrial, gallbladder, kidney, oesophagus, and breast and colon cancer. Other foods linked to cancer are pickled and heavily salted foods and alcohol. Artificial sweeteners like cyclamate, saccharine and aspartame are considered safe for humans. Burnt or overheated foods (like barbecued foods) have higher levels of carcinogenic PAHs. 

 

Lack of physical activity 

Lack of physical activity is linked to cardiovascular diseases, obesity and diabetes. However, it is related to a higher risk of certain cancers. The research is undergoing to understand the relationship. However, the researchers have noted that poor lifestyles and physical inactivity cause hormonal imbalances and increase the risk of cancers associated with hormone levels like ovarian and endometrial cancer. 

Physical inactivity reduces insulin sensitivity causing diabetes. Diabetes results in a persistent low-level inflammation in the body which is a cause of cancer. Physical inactivity allows the carcinogens present in the food to have more contact time with the lining of the intestines. Screen time is a measure of physical inactivity, and increased screen time is likely to increase exposure to the advertisements of high-energy foods and sugary drinks that cause weight gain and increase the risk of cancer. 

 

High alcohol consumption

High alcohol consumption means consuming more alcoholic beverages than recommended for the specific gender and age. The recommended levels for most men and women are 2 drinks and 1 drink per day, respectively. Drinking alcohol and hefty drinking increases the risk of breast, colorectal, liver, oesophageal, and cancers of the larynx (voice box), throat, and mouth. Alcohol consumption is the cause of 4% of cancer cases worldwide.

Research shows that consuming three or more drinks daily causes an increased risk of pancreatic, prostate and stomach cancers. All alcoholic beverages like liquor, beer, and white and red wine are associated with cancer risk, and higher drinking levels increase the risk of cancer. There are multiple ways alcoholic beverages increase the risk of cancer. These include;

• The ethanol in alcoholic beverages is metabolised to produce acetaldehyde, a toxic human carcinogen. It damages the DNA of cells and causes cancer-causing genetic mutations. 
• Alcohol metabolism causes increased production of reactive oxygen species (free radicals) that damage the cellular lipids, proteins and DNA by oxidation. 
• Heavy alcohol consumption lowers the digestion and absorption of certain nutrients that reduce the risk of cancer, like vitamins D, E, C, and B complex, carotenoids, folate and vitamin D.
• Heavy alcohol consumption increases the levels of some hormones like oestrogen that increase the risk of breast cancer. The low-quality alcoholic beverages often contain various carcinogenic contaminants produced during the manufacturing and processing like hydrocarbons, phenols, asbestos fibres and nitrosamines.

 

Unprotected exposure to UV light 

Ultraviolet radiation (UV) is a form of high energy electromagnetic radiation emitted by the sun and produced by various man mad sources like welding torches and tanning beds. Multiple types of UV light exist, which are based on their energy. The high-energy UV light has ionizing effects and damages the DNA of the cells leading to cancerous mutations. Sunlight is the primary source of UV light, but most (95%) are of low energy and cause long-term effects like wrinkles. The remaining 5% are of high energy and cause damage to the cellular DNA. 

The artificial UV light sources are sunbeds, sunlamps, black light lamps, mercury vapour lamps, welding arcs, plasma torches and high-pressure xenon Mercury arc lamps. Most skin cancers, particularly those of squamous and basal cells, are caused by UV light. Exposure to sunlight and artificial UV light sources increases the risk of skin melanoma. The damage to the skin due to sunburns is too linked to the risk of skin cancer. It must be remembered that everyone exposed to UV light doesn't necessarily develop skin cancers; such people only have a higher risk than unexposed people.

 

Certain virus infections

Viruses are microscopic infectious agents that replicate in a host and cause diseases. There are many viruses known as oncoviruses that cause cancers. The oncoviruses have genes made of DNA and RNA, and different viruses cause diseases by other mechanisms. The oncoviruses cause cancers through a complicated process, and the exact mechanism is not fully understood. However, it is known that these viruses insert their genes into the DNA of the host cells and cause dangerous mutations resulting in cancerous transformation. Examples of oncoviruses are;

Epstein Barr virus (EBV): It belongs to the family of herpes viruses. The EBV infections cause an increased risk of stomach cancer, Hodgkin's and non-Hodgkin's lymphoma, and Burkitt's lymphoma. No vaccine is available against it. 

Hepatitis B virus: It is spread by body fluids, e.g., infected semen and blood and is a significant cause of liver cancer. Its vaccine is available and must be administered. 

The Hepatitis C virus: It is spread by infected blood and is a significant cause of non-Hodgkin's lymphoma and liver cancer. It is treatable, but no vaccine is available for it.

Human herpes virus 8 (HHV-8): It causes Kaposi's sarcoma in immunocompromised people, e.g., HIV patients.

Human papillomavirus (HPV): At least 12 viral strains in the HPV group cause different cancers like cancers of the vulva, vagina, throat, penis, cervix and anus. Its vaccine is available and must be administered at a young age. 

Human T-lymphotropic virus (HTLV-1): It causes T cell lymphoma/leukaemia in adults and is spread through body fluids like semen, breast milk, vaginal fluids and semen. 

Human immunodeficiency virus (HIV): It spreads through infected body fluids like semen, breast milk, vaginal fluids and semen. It attacks the immune system and reduces the ability of the body to fight oncovirus infections and kill its virus-mutated cells. No vaccine is available against it. HIV is associated with cancers of the lungs, throat, anus, liver, anus, cervix, Hodgkin's and non-Hodgkin's lymphoma and Kaposi's sarcoma.

 

What are the Complications of Cancer?

The complications of cancer depend upon the organ of origin and the extent of metastasis. The difficulties are rare if cancers are diagnosed earlier. The complications result from the primary or secondary tumours that develop at the sites away from the original site. Death from cancer is the outcome of these complications. These include;

Malnutrition: It is the main cause of death in advanced stages of cancer. It particularly happens if a large size tumour in the digestive system interferes with the absorption of nutrients or causes a physical obstruction in the flow of digesta. Many cancers and anticancer treatments result in loss of appetite and poor digestion. Malnutrition results in loss of lean body mass, cognitive difficulties, muscle wasting, fatigue and poor immunity, which increases the risk of other infections. Malnutrition results in poor response to treatment and poor survival. 

Oxygen deficiency (hypoxia): The primary function of the lungs is to supply oxygen to the blood and remove carbon dioxide. Lung cancers damage the lungs and occasionally cause them to collapse. A collapsed lung is challenging to treat, develops more severe infections and cannot supply enough oxygen and remove waste gases resulting in difficulty breathing and death. 

Liver damage: The liver is the centre of metabolism and has many essential functions like maintaining a balance of different chemicals in the body, metabolism of drugs and detoxification of toxins. Liver damage due to liver cancer results in the loss of these essential functions and death. Some signs of liver damage are yellowing of skin and eyes, dark-coloured urine, bloating, abdominal swelling, poor appetite, pain in the upper right abdomen, nausea and weight loss. 

Higher calcium levels in the blood: Normal calcium levels of 8.5-10.5 mg/ dL are essential for muscles, kidneys and heart function. Some cancers, like bone cancer, cause excessive calcium release from bones into the blood, causing very high calcium levels. It results in depression, loss of memory functions, confusion, coma and death in advanced cases. 

Higher risk of infections: Different factors associated with cancer, like a low number of white blood cells, malnutrition and damage to multiple organs, cause immunosuppression and lower the ability of the body to fight infections and kill the cancerous cells. It results in a high rate of infections, rapid spread of cancer and poor survival from common diseases.

Blood and vascular problems: Caners sometimes invade the blood vessels causing severe damage and risk of stroke. The involvement of bone marrow influences the production and maturation of blood cells like white blood cells that fight infections, platelets that are involved in wound healing and red blood cells that supply oxygen to the body tissues. There are immature cells in circulation with poor functional abilities. 

Bone pain: Bone pain is the complication of the metastatic spread of cancer as bone is the common site of metastasis of cancerous cells. The common cancers that spread to the bones are the cancers of the thyroid, kidney, breast, prostate, and lungs and other cancers like lymphoma and multiple myeloma. It severely reduces the quality of life and survival rate. 

Brain complications: The cells from some cancers, like breast cancer, spread to the brain. The metastasis to the brain is an alarming sign as it affects essential body functions controlled by the brain, causing problems with behaviour, memory and vision. Other associated symptoms are seizures, nausea, vomiting, dizziness and headaches.

 

How does cancer multiply and spread? 

Cancerous cells are abnormal cells whose DNA has been damaged. So, these cells' progeny cells are different from the normal cells. As there is no control over the multiplication of cancer cells (like in normal cells), an uncontrolled amount of growth happens quickly. Cellular adhesions bind the normal cells. Cancerous cells break from adhesions, reach multiple sites via circulating blood and lymph, and cause secondary tumours at distant locations. These cancerous cells produce the same chemical signals and growth produced by healing wounds or normal tissues. The growth signals cause the formation of blood vessels in the tumours. These blood vessels supply the essential nutrients, oxygen, growth hormones and sugars that allow the cells to proliferate. 

As billions of cells are regularly produced and die inside the body, having some abnormal cells is perfectly normal as the immune system hunts these cells and kills them. However, cancer cells resist these signals and don't die when needed. The immune system fails to hunt them down, and the production cycle of new cancerous cells continues.

 

What are the Stages of Cancer?

An oncologist uses staging of cancer to describe its size, location, spread from the primary site, etc. Before the start of treatment and to monitor the effects of treatment, the doctors use scans, imaging and physical examination to stage the cancer. The progression of cancer and its spreading causes an increase in stages over time, while effective treatment causes decreasing stages over time. Staging helps doctors predict the disease outcome as advanced settings are associated with poor results. 

For the majority of cancers, the oncologists use the TNM system for staging, where T stands for tumour (T), N stands for lymph nodes, and M stands for metastasis. The letter T describes the size and location of the primary tumour, and the N number reflects if the tumour has affected the local lymph nodes. If yes, how many lymph nodes are involved? The letter M describes the presence and extent of metastasis.

Traditionally, there are four stages of cancer named I to IV. Sometimes, an additional '0' stage is added to the list. Various characters of different stages are;

Stage ‘0’: Stage '0' describes cancer in situ or cancer in place. It means the cancer is limited to the primary development site and has not spread to the surrounding tissues. Cancer at 0 stage is curable, and there is a good prognosis. Routine screening is done to detect cancer at stage '0'.

Stage I: The cancer at stage 1 has spread to the surrounding tissues but not too deeply. Only some local tissues are involved and no regional lymph nodes or distant tissues are involved. It is in the early stages, and there is still a good chance of complete recovery.

Stage II and III: These cancers have grown deeply into the local tissues, and regional lymph nodes are involved. However, there is no metastasis, and there is no spread to other areas of the body. Sometimes, it is impossible to completely treat the cancers at stage III, and the patient's chance of survival for the next 5 years is estimated. 

Stage IV: It is a highly advanced and metastatic form of cancer. The cancerous cells have spread to other body areas, and there are multiple secondary tumours at various sites. It is impossible to completely treat cancer at stage IV as the chance of survival for the next 5 years is low. Only palliative care is done to improve the patient's quality of life. 

Sometimes, restaging is done to understand the response to the treatment and the resurgence of cancer. 

 

How is Cancer being diagnosed?

The earlier diagnosis improves the chances of successful treatment and survival. The cancers of the mouth, breast, testicles, rectum, prostate and skin are detected during routine physical examination. Most of the time, the tumour is detected as the tumour grows or other signs become noticeable. In a minority of cases, Cancers are diagnosed during the monitoring or treatment of other cancers. The diagnosis of cancer involves the following steps;

Physical examination and history: The first step in diagnosis is a thorough physical examination and taking a case history. 

Laboratory testing: Then, laboratory tests are conducted on the stools, urine, and blood to check for any cancer-related abnormalities. Once these tests reach a presumptive diagnosis, imagining techniques like computed tomography (CT) scan, ultrasonography, magnetic resonance imaging (MRI), x-rays, and endoscopy help the doctors judge the tumour's size and location. Occasionally, a tissue sample is taken using biopsy needles, and examples are sent to the laboratory for histopathology that detects the extent of abnormalities by microscopy. In case of positive tests, further diagnostic tests are conducted for staging purposes, which is helpful for treatment. 

Retesting: If the symptoms persist despite negative tests, retesting and testing for other health conditions are recommended.

 

How is Cancer Prevented?

Early diagnosis of cancer is essential for early and successful treatment. However, once cancer is established, the complete cure becomes very challenging. According to the World Health Organization, 30-50% of cancer cases are preventable by avoiding exposure to risk factors and making lifestyle modifications. Prevention is the only cost-effective and long-term viable option. Here are some worthy options.

Avoid using tobacco and tobacco products: There are no safe levels of chemicals present in tobacco smoke. Therefore, it is essential to limit or completely eradicate the use of tobacco products. Even the exposure to secondhand smoke is hazardous. 

Improve your diet: Red meats and saturated fats increase the risk of colorectal and prostate cancers. Replace them with whole grains, fruits and vegetables and consult the nutritionist for complete guidance. 

Regular exercises: Physical exercises are linked to the reduced risk of various cancers, including breast cancer in women. It improves digestion and reduces the contact time of various carcinogenic contaminants in the food. Spending 30 minutes or more daily or at least 150 minutes weekly on physical activities is a worthy option. 

Stay lean: Obesity is linked to the risk of various cancers. So, a person must reduce calorie intake and burn dietary calories through exercises to reduce fat and lean mass. 

Limit alcohol consumption: Excessive alcohol consumption increases the risk of various cancers in the colon, oesophagus, liver, mouth, larynx and even breast cancer in women. It increases the risk of malignancies. So, alcohol consumption must be limited to not more than 1 drink per day for women and 2 per day for men. 

Reduce radiation exposure: Medical imagining is sometimes necessary. However, it must be done only if asked by the doctor. Moreover, the home must be tested for radon and other radioactive matter. People must adopt protective measures for sunlight to limit exposure to UV light. 

Limit the exposure to environmental and industrial waste: Industrial and ecological waste often has many carcinogens like polychlorinated biphenyls, aromatic amines, benzene and asbestos fibres, and exposure to it must be avoided. 

Prevent oncogenic infections: Oncogenic viruses like human papillomavirus, HIV and hepatitis cause various cancers. People must be vaccinated against them and must use preventive measures. 

Focus on sleep: Poor sleep or sleep deprivation causes various negative changes in the body, including cancer. The link between sleep with cancer is fragile. However, it increases multiple other risk factors of cancer, like obesity. 

Improve the intake of essential vitamins: There is no proven association. However, vitamin D supplementation is known to lower the risk of some cancers like colorectal and prostate cancers. The experts recommend taking 800-1000 IU of vitamin D through diet and supplements. 

 

Is there a link between diabetes and cancer?

A strong relationship exists between type 1 and type 2 diabetes and cancer. Some epidemiological studies have noted that cancer is the second most important cause of fatality in patients with type 1 diabetes, while 8-18% of cancer patients have diabetes. Type 1 diabetes increases the incidence rates of leukaemias, squamous cell carcinoma, and cancers of the thyroid, stomach, lung, oesophagus, kidney, pancreas, and liver for both genders. Likewise, some other cancers with increased risks due to type 1 diabetes are cancers of the vagina, vulva, endometrium, and ovary in women. The association is not always linear, and it is noted that the incidence rates of testicular and prostate cancers are lower in men having type 1 diabetes as compared to the general population (Harding and colleagues, 2015). Similarly, the risk of Hodgkin's lymphoma, melanoma, and breast cancer in women with type 1 diabetes is less than in general population.

The results of studies linking type 2 diabetes with cancer are very inconsistent. A large-scale meta-analysis published in the BMJ in 2015 noted that type 2 diabetes causes a 10% increase in the risk of cancer. The highest risk in the population with type 2 diabetes is that of colorectal, liver, and pancreatic cancer. Likewise, the chances of some cancers decrease with type 2 diabetes, like laryngeal cancer and cancers of the urinary bladder, lungs, oesophagus, oral cavity, and brain.

So, an inconsistent link exists between cancer and diabetes, with the incidence of some types increasing and that of others decreasing. Generally speaking, having diabetes adds to cancer and cancer treatment complications. Diabetes is linked to an increased risk of cancer-related mortality and poor survival. Despite the indications of a strong link, the exact mechanisms of how diabetes causes cancer are not fully understood, and research is underway to understand these links. 

 

Is exercise helpful in preventing cancer?

Yes, regular exercise and staying active all day improve wellness and reduce the risk of some diseases like cancers. Regular Exercises help a person maintain physical fitness and prevent obesity, the risk factor for 13 types of cancers. It helps regulate the levels of hormones to prevent the development of hormone-related cancers. It improves the functions of the liver and digestive system, allowing better detoxification of toxins and lowering toxin production in the bowel. 

Several mechanisms responsible for the low risk of cancer due to regular physical exercises are a decrease in obesity-related cytokines, levels of sex hormones, hyperinsulinemia and systemic inflammation. Likewise, physical exercises improve the diversity and composition of useful microbes in the intestines and boost immune functions. 

 

What is the treatment for cancer?

Different modalities for cancer treatment are available, and the choice depends upon the type of cancer and the extent of its spread. Sometimes, only one treatment (for localized and non-metastatic cancers) is enough. For more advanced cancers, a combination of different therapies is used. Each treatment has pros and cons, which must be discussed with the doctor. While it is natural to be overwhelmed by the thoughts of having cancer, it is counterproductive and maintaining morale and motivation is crucial. Some treatment options available for cancer are;

Chemotherapy

In chemotherapy, the drugs are used to target and destroy the cancer cells. The drugs used during chemotherapy restrict the growth of cancerous cells by inhibiting the chemicals involved in cell division. As fast-growing cancer cells secrete various growth-related factors.The chemotherapeutic drugs are able to locate and kill them. These drugs damage the healthy cells too, causing nausea, hair loss and other symptoms. Multiple modes of chemotherapy are oral chemotherapy, intravenous chemotherapy, chemotherapy into the abdomen and peritoneum and topical chemotherapy. The primary chemotherapeutic drugs used are mitotic inhibitors, plant alkaloids, anti-tumour antibiotics, topoisomerase inhibitors, antimetabolites and alkylating agents.

Hormone therapy 

It is used to control the growth of tumours that develop due to hormonal changes. It is used to stop or slow the growth of prostate, ovarian, uterine and breast cancers. It works by blocking the supply of essential enzymes used by the cancer cells for growth and multiplication. For example, the hormones oestrogen and progesterone influence the development of breast cancer, and breast cancers are classified as oestrogen-positive (ER+), progesterone-positive (PR+) or positive for both. The hormone therapy drugs like tamoxifen, aromatase inhibitors, LH blockers, and fulvestrant block the supply of these hormones to the cancer cells. 

Hyperthermia

During hyperthermia, the cancerous tissues are heated at 113F or higher to damage and kill them. It uses different devices to focus the heat on the cancerous cells and prevent damage to the normal tissues. Various treatment modalities used for hyperthermia are probes that release high energy waves, lasers, ultrasounds, heating the fluids, e.g., chemotherapeutic drugs and blood and injecting them into the blood and the use of a hot chamber, hot water bath or heated blankets. It is used for different cancers like rectal cancer, sarcoma, mesothelioma, melanoma, lung cancer, liver cancer, neck and head cancer, oesophageal cancer, cervical cancer, brain cancer, bladder cancer and appendix cancer. 

 

Immunotherapy

It is aimed at boosting the immune system to help fight cancers. Different types and modalities of immunotherapy are immune checkpoint inhibitors, monoclonal antibodies, nonspecific immunotherapies, cancer vaccines, T-cell therapy and oncolytic virus therapy. 

Photodynamic therapy

It uses a light-activated drug to target and destroy cancerous and abnormal cells. The light used in phototherapy comes from various sources like lasers and LEDs. It is an excellent local treatment which selectively targets cancerous tissues. The light-activated drug is known as photosensitiser. The cells that absorb photosensitiser are then exposed to high-energy radiation. The radiations cause the production of free radicals from the photosensitiser that kills the cells. It sometimes triggers the immune responses to kill the cancer cells, damages the blood vessels in the tumour, and deprives the tumour cells of nutrition. It is used for various cancers like oesophageal cancer, basal cell skin cancer, actinic keratosis, T lymphoma etc.

Radiation therapy 

It uses high doses of radiation and waves to kill the cancer cells. It restricts the growth of cancer cells and causes shrinkage of the tumours. The higher doses of radiation kill the cancerous and precancerous cells by destroying DNA. It doesn't give quick results, and many sessions are required as the irreversible damage to the DNA takes time to kill the cells. Different modalities are internal radiation therapy and external beam radiation therapy.

Stem cell transplant

Stem cells have the potential to differentiate into multiple types of cells. The stem cell transplant replaces the stem cell population in the bone marrow pool, where defective stem cells produce lousy blood cells. Sometimes, it is used to replace the depleted population of stem cells that are consumed by cancer therapies. The bone marrow transplant is most commonly used as most stem cells are in the bone marrow. Different modalities of transplant are:

• The autologous transplant, in which the stem cells are taken from the body of the recipient itself.
• Allogenic transplant, in which the stem cells are taken from another donor person.
• Umbilical cord blood transplant, in which the stem cells are taken from the blood in the umbilical cord 
• Parent-child transplant, in which the stem cells are taken from the children or parents of the patient. 

Surgeries 

The tumour and some adjacent tissues are removed during surgical procedures, which is more successful in localized cancers. Some adjacent tissues are removed alongside the primary tumour to reduce the chances of treatment failures. In the case of metastatic cancer, surgical treatment must be combined with other therapies. 

 

Targeted therapy 

It targets different changes in the canner cells that occur due to rapid spread, growth and proliferation. It targets the proteins that control the growth and expansion of the cancerous cells. It is a type of precision therapy, and more research is underway to explore new targets.

 

Is radiation therapy a standard cancer treatment?

Yes, radiation therapy is a commonly used standard anticancer treatment. It uses high-energy electromagnetic radiations to target and destroy the cancer cells. The radiations damage the cells' DNA, thus diminishing the cells' ability to multiply and causing the shrinkage of tumours. External beam radiotherapy uses a beam from an external source, and internal beam radiotherapy uses radiation from an internal source. A radiation source is placed inside or close to the tumour in the latter type. If planned and executed carefully by an expert radiologist, radiotherapy gives excellent success rates.  

 

Is the cancer treatment effective?

Yes, cancer therapy is very effective, particularly for the early stages of cancer. The effectiveness of cancer treatment depends upon multiple factors like the stage of cancer, age and health status of the patient and the treatment modalities used. The primary goals of anticancer therapies are to improve the patient's quality of life and the chances of 5-year survival. Patients with early-stage cancer benefit from surgeries and radiotherapy. Patients with advanced cancers usually don't fully recover, and 40-50% experiences another resurge in a few years and die of the cancer complications. 

The cure depends upon the cancer stage, and the probability of survival for the next 5 years decreases with the advancing form of cancer. Complete recovery in advanced cases is challenging. The success rate depends upon the nature of the treatment used.

 

What is the difference between cancer cells and normal cells?

The cancerous cells are markedly different from the normal cells. Significant differences exist in their growth rate, appearance, cellular communications, ability to spread to other tissues, immune evasions, blood supply, and stickiness. 

Cancer cells have the potential to divide rapidly and have many features of rapidly dividing cells, like a high ratio of spindle fibres and the presence of mitotic apparatus. They are able to overcome suicide and other inhibitory signals that inhibit cell growth when needed. Mature cells have a regular lifespan, while the lifespan of cancerous cells is irregular. The cancerous cells are resistant to the signals from other cells that warn about overgrowth. Regarding shape, the shape of normal cells is more uniform and very similar to as needed for that particular type. The cancerous cells don't have a uniform shape. 

When damaged, the normal cells die or repair themselves, while the cancerous cells don't fix themselves and continue to carry on the abnormal mutations. The normal cells stay on the development site while the cancerous cells detach from their development site and invade adjacent and distant places in advanced cases. When damaged, the normal cells are identified and removed by the immune system. The cancerous cells, on the other hand, are able to dodge the immune system and survive with abnormal mutations. The regular cells release chemicals that cause them to stick together and form cellular adhesions. Such adhesive substances are not formed by the cancerous cells; they roam freely in circulation and the lymphatic system.