Signs and Symptoms of Bowel Cancer

Signs and Symptoms of Bowel Cancer - welzo

Bowel Cancer: An Overview

Identify the bowel cancer (also called colorectal cancer/ colon cancer) with these symptoms before it is too late.

The word bowel means intestines. So large bowel means large intestine, and small bowel means small intestine. The term bowel cancer is used primarily for large intestine cancer because small bowel cancer is considered to be rare.

The large bowel has three parts: caecum, colon, and rectum. Cancer usually develops in the colon and the rectum. So, if you have colon cancer, it is likely that you have an increased risk of rectal cancer. The term colorectal cancer also means bowel cancer. It is a highly prevalent cancer in the UK.

What should you know about bowel cancer (colorectal cancer)?

Human life is precious. As the saying goes, prevention is better than cure. Reading about bowel cancer will make you aware of any signs or symptoms to look out for. A recent report published by the National Institute for Health and Care Excellence has enlisted colorectal cancer as the 4th most common cancer in the UK, with over 41,000 cases diagnosed in a year on average.

The period 2017-19 saw 16,800 deaths annually (46 each day). So, any signs of bowel cancer should not be overlooked. If you would like a more comprehensive overview of cancer, read our symptoms and causes of Cancer article.

Why is early diagnosis important?

Like all other type of cancers, early diagnosis increases the chances of successful treatment. A late diagnosis will result in the spread of disease to various parts of the body (metastasis) and a poor clinical outcome.

How can it be diagnosed?

The diagnosis of bowel cancer revolves around;

  • Laboratory tests;

  • Clinical signs and symptoms

For your health, you should know the clinical signs of colon or rectal cancer. However, a clinician will need laboratory confirmation for a successful treatment. What signs and symptoms will you note? Let's introduce some bowel cancer symptoms that should alert you.

Change in bowel habits

Cancer can change your bowel habits. The stool can become hard (constipation) or soft (diarrhoea). The defecation reflex (the cause of the expulsion of faeces) can become overactive, and you can feel the need for defecation without any faeces removal. If you spend more time in the toilet and still feel no satisfaction, it is the time to consult the doctor.

Also, note the presence of blood or pus in the stool and also note if it is very loose. You must undergo clinical examination if this bowel movement disturbance does not respond to any treatment.

Dark stool

Blood in faeces could be due to several other causes, e.g., bacterial infections, parasitic infestations, etc., but don't ignore it. If the blood is bright red (fresh), it is likely due to piles (in the rectum).

However, black and dark brown stools are also noted in highly developed bowel cancer. The presence of blood will make your stools darker (tarry stools). Such stools could be due to ulcers in the stomach or cancerous lesions in the bowel. Consult your physician immediately.

Weight loss

Weight loss is a complex problem and can be due to several causes. The weight loss coupled with a history of loose and darker stools could be a sign of bowel cancer. Prolonged diarrhoea will result in weight loss due to dehydration and loss of vital nutrients.

Any weight loss of 5kg or more in the last 6-12 months should raise your eyebrows.


Colon cancer can disturb the homeostasis of iron in the body. This iron is necessary for the formation of red blood cells. So, if you have cancer in the large bowel, the resulting lack of iron will cause you to become anaemic.

An additional cause of anaemia is the loss of blood due to bleeding. This bleeding occurs because the growth of tumour tissue is associated with the formation and rupturing of blood vessels in the colon.

The symptoms associated with anaemia will be noticed, e.g., the thinness of blood, fatigue, tiredness, shortened breath, paleness of skin and mucous membranes (of mouth and eyes).

Painful lump in the abdomen or intestines leading to blockage

What is cancer? It is the out-of-control growth of cells resulting in a clump of cancer cells. Such a clump in the abdomen will disturb your eating and sleeping habits. If such a lump has developed in the last part of your bowel, you can feel its presence while in the toilet. This lump can make defecation excruciating, and even a complete bowel obstruction can develop.

Research published in the Romanian Journal of Gastroenterology has found that bowel obstruction is a significant complication in bowel cancer. The abdominal pain or pain in the back passage can also be due to a lump.

What other symptoms can you note?

Besides these symptoms, you can also note some other problems, e.g.,

  • Ulcerative colitis: It is a painful condition in which ulcers can develop in your colon.

  • Crohn's disease (an inflammatory bowel disease)

  • Anal fissures: It is a superficial and very painful tear in the moist lining of the anus.

  • Irritable bowel syndrome

  • Diverticular disease in which small pockets form in the intestines.

  • Diarrhoea and constipation

Keep a record of these symptoms in a diary and go to the general physician with a complete history of symptoms.

When do you need to visit the doctor?

It is suitable to visit the doctor if these symptoms persist and you do not feel any better. The GP will start with a physical examination of your rectum and abdomen to see any lumps.

He can suggest serum mineral analysis to see any iron deficiency. The physical examination of faeces can also reveal the nature of bleeding in your faeces.

Bowel screening services are offered in the UK if you are 60 years of age or more. However, you can request a test kit even if you are past 74. Routine bowel cancer screening can help with diagnosis. If you are aged 60 or more, take a protein-rich diet, are overweight, have a sedentary lifestyle, alcoholic or a regular smoker, or have a family history of bowel cancer, etc.

Once the presence of cancer is confirmed, your doctor will recommend the next course of colon cancer treatment, whether you need radiotherapy, chemotherapy, or surgery.


Early detection is necessary for successfully beating bowel cancer. The good news is that it is curable if diagnosed at the right time and at an early stage. Your health is your responsibility. So keep a vigilant eye on the signs and symptoms of bowel cancer and immediately go to the hospital if you feel some or more of these symptoms.

The national cancer institute also provides guidelines about the diagnosis of colorectal cancer.

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