The most critical and advanced stage of colon cancer is stage 4. As per cancer research UK, bowel cancer comprises the second cause of cancer death and the fourth most frequent disease overall. Bowel cancer will be discovered in 1 in 15 men and in 1 in 18 women throughout their lifetime. Stage 4 colon cancer has a 5-year survival rate of little under 15%. This suggests that approximately 15% of persons with stage 4 bowel cancer will survive 5 years.

Bowel cancer is classified into four phases, extending between stage 0 through stage 4. Stage 0 is the first sign of cancer. It is discovered even before cancer cells have progressed through the colon's interior lining. Stage 4 is when cancer cells inside the bowel have migrated (metastasized) to another section of the body.

Stage four bowel (colon as well as rectal) cancer indicates that the disease has progressed to other organs, including the liver and lungs. It is also known as advanced bowel cancer.

Colon cancer at stage IV can be very painful and challenging. Patients may feel bloated and have cramping in their stomachs. Long, thin faeces are also frequently accompanied by diarrhoea and constipation. In addition, there is generally weight loss, general weakness, and weariness.

 Read more: Signs and symptoms of bowel cancer.

Characteristics of Stage 4 bowel cancer

Colon cancer is classified as stage IV based on three basic characteristics of cancer: the tumour (T),  lymph nodes invasion (N) where cancer often spreads initially, and metastasis (M). M stands for cancer spread to additional organs or parts of the body. Metastases from colon cancer most commonly spread to the lungs and liver.

The tumour (T)

Doctors specifically assess the extent to which it pierced the bowel or rectum wall and the overall size of the tumour. The layers in this area range from the inner layer to the delicate outer layer of connective tissue that covers the bowel (but not the rectum).

The lymph node (N)

How far has the cancer spread from the lining of the bowel or rectum to neighbouring lymphatic nodes in the body? This is significant because, like your systemic circulation, lymph nodes are located throughout your body. Cancer can spread by gripping your lymph nodes and transferring them to other parts of your body.

Metastasis (M)

Bowel cancer has progressed to further lymph nodes and other regions, such as the liver and lungs. This is the primary emphasis and distinguishing feature of stage IV. This is also why this is the most challenging stage to treat. Rarely, it may also extend to the brain, ovaries, bones and other body organs.

Stage 4 is broken into three categories: 4A, 4B, and 4C.

1.      4A Stage

Stage 4A cancer has progressed to one distant place or organ, such as the liver, but not to the membrane lining of your stomach (peritoneum). The cancer cells spread along through lymphatic or circulation systems.

2.      4B stage

Stage 4B cancer has progressed to two or more distal organs but not to the membrane lining your stomach (peritoneum).

3.      4C Stage

Stage 4C indicates that the disease has migrated to multiple organs and the inside of your stomach (peritoneum).

Diagnoses of stage 4 Bowel Cancer

Bowel cancer screening can detect the disease. Screening is currently recommended for individuals aged around the groups of 45 and 75 years age. Screening for colon cancer may occur sooner if you are at a higher risk. There are numerous screening techniques available. The following are the most popular screening methods:

Faecal blood test:

The test detects blood inside the stool using chemicals.

Faecal immunochemical (FIT) testing:

This FIT test detects blood in the faeces using antibodies. Usually, it is carried out once a year.

Feces-DNA (FIT-DNA):

This testing detects blood and aberrant DNA in the stool, such as big polyps and cancer growth. Every three years, the test is performed.

Colonoscopy:

This procedure examines the entire colon and rectum with a larger scope. During the exam, clinicians eradicate polyps and early malignancies. This test is considered the gold benchmark for detecting colon cancer. For a person at average risk, a colonoscopy is undertaken every ten years. It can be conducted more occasionally if necessary.

Flexible sigmoidoscopy:

This examination examines the final part of the colon and rectum with a thin, flexible scope equipped with a camera. During this process, health professionals can remove any polyps or early malignancies discovered. An annual stool test is used to perform over 5 to 10 years.

According to cancer research UK, Nearly 2 million people in the UK are referred to hospitals each year due to bowel complaints, where they receive investigations (often via a colonoscopy, which involves inserting an endoscope, a camera, into the gut to inspect it). Now various proficient bowel cancer home tests are also available.

 Read more: Is bowel leakage a sign of cancer?

 

What treatment options are available for stage four bowel cancer?

A diagnosis of fourth-stage colon cancer indicates that the illness has spread far and wide. The amount of the tumour's dissemination determines the course of treatment. Anyone who is diagnosed with stage 4 colorectal cancer must make some considerations about their next steps, particularly about treatment options. It is critical to review all of your options with your doctor and understand the purpose of each treatment.

Treatment choices for persons with stage 4 bowel cancer are far more constrained than those for people with early phases of this malignancy. The therapeutic goal in many patients of stage four colon cancer is really to extend your life. However, there are certain medication choices to explore, as well as some other variables to consider.

Surgery:

Surgery is improbable to cure cancer once malignant cells have migrated to other organs and tissues. However, in rare circumstances, surgery could still be a viable alternative. Surgery may continue to be an option if a scan indicates that the tumours have only progressed to a few minor locations. Health professionals want to help the patient live longer by removing the malignant cells.

These procedures will necessitate the removal of a portion of the bowel as well as adjacent lymph nodes. Additional surgery may be required to remove the portions of tissue where the cancer has progressed. Typically, doctors will recommend chemotherapy either before or following surgery. Doctors may also advise a diversion colostomy, which involves cutting the colon just above malignant tissue and directing the bodily waste through a small incision in the skin.

Read more: What are bowel polyps?

Systemic chemotherapy:

Systemic chemotherapy is the preferred treatment strategy if somehow the colon cancer has progressed far enough for surgery to be successful. To help manage cancer's growth or symptoms, most individuals diagnosed with stage 4 bowel cancer will get chemotherapy or specialized targeted therapies.

Chemotherapy aids in the killing of the body's tumour cells and the prevention of future spread. Specialists may recommend it before, after, or instead of surgery. This is determined by the extent and site of the cancer dissemination. Systemic chemotherapy can be administered via tablet or intravenous (IV) administration to the body.

Ablation:

When bowel cancer has only migrated toward the liver, patients can receive chemotherapy targeting the liver. This prevents the remaining body organs from receiving the medicine, lowering the likelihood of negative effects. Another method of killing cancer cells that have advanced to the liver is ablation. Ablation may be acceptable for persons with metastatic or recurring colorectal cancer that forms a few tumours smaller than 4 centimetres wide in the lung or liver.

Ablation targets and kills cancer cells while leaving surrounding tissues relatively unscathed, using radio waves, lasers, or alcohol — commonly known as percutaneous ethanol injection (PEI). A doctor may inject chemicals into the bloodstream to try to restrict or reduce blood supply to cancerous cells in the liver during embolization.

Radiation Therapy:

Radiation therapy is usually only recommended in complicated diseases of colon cancer. This aids in the relief of symptoms such as discomfort and bleeding. Selective internal radiation therapy may cause the tumour to shrink rather than kill cancer cells, so it does not treat it.

Palliative care:

Whenever a patient's cancer has spread and colorectal cancer is incurable, palliative care medications may persist in easing pain, relieving symptoms and improving general health. Surgery, for example, may excise certain cancer tissue, bypassing the most severely afflicted portions of the colon, or install stents. Other operative goals may include reducing tumour bleeding, relieving stomach pain, or removing a colon obstruction. Colorectal cancer treatments are frequently limited at stage IV, depending on the patient's preferences and personal circumstances.

 

Bottom line:

While stage IV bowel cancer is the hardest for victims to survive, treatment options are constantly increasing, thanks partly to clinical studies. Some stage IV individuals live for longer periods and are even rehabilitated. Palliative care, which could halt cancer and keep people as comfortable as possible, is the main focus of this period. The assistance of family, friends and even the community could make the biggest difference during this time.