Bowel cancer symptoms: What to look out for

Did you know bowel cancer is the fourth most common cancer in the UK and the second most deadly cancer? According to Cancer Research UK, nearly 43,000 people in the United Kingdom are diagnosed with bowel cancer every year. So let's look at the bowel cancer symptoms you need to look out for.

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Last updated and fact checked:
Bowel cancer symptoms: What to look out for
  • Nearly 43,000 people in the United Kingdom are diagnosed with bowel cancer.
  • Doctors advise people with an average risk of bowel cancer to begin colon cancer screening around 45.
  • In the UK (NHS), many treatments are available to help control bowel cancer, including surgery, radiation therapy, and drug treatments such as targeted therapy, chemotherapy, and immunotherapy.
  • A person may experience bowel cancer symptoms of unexplained weight loss, blood in their stool, or rectum bleeding.

Bowel cancer symptoms: FAQs

  • What are the most common symptoms of bowel cancer?

    The most common symptoms of bowel cancer are changes in bowel habits, such as diarrhoea, constipation, or the sensation of incomplete emptying and bloody stools.

  • What should you do if you have any bowel cancer symptoms?

    Consult your doctor if you have any bowel symptoms or a close family history of cancer. If you have had bowel cancer screening, any symptoms should be reported to your doctor as soon as possible for further medical referral.

  • What is the difference between colon cancer and IBS?

    IBS and bowel cancer have similar symptoms. However, in the case of bowel cancer, a person may experience unexplained weight loss, blood in their stool or rectum bleeding that does not occur in IBS.

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The bowel is a part of the digestive system divided into two sections: the small and large bowel. The colon, rectum, and anus are part of the large bowel.

Bowel cancer is also known as colon or rectal cancer, based on where the cancer starts.

According to Macmillan Cancer Support, colorectal cancer is a combination of colon and rectal cancer that starts in the rectum.

Many people have no symptoms of bowel cancer in its early stages. But here are common signs and symptoms to look out for:

  • A consistent change in bowel habits, such as diarrhoea, bowel obstruction, constipation, or a change in stool consistency
  • Blood in your stool or rectal/stoma bleeding
  • Consistent abdominal pain, bloating, cramps, gas, or discomfort
  • A sensation that your bowel does not completely empty even after taking laxatives
  • Weakness or exhaustion
  • Anal or rectal discomfort
  • A lump/tumour in the rectum or anus
  • Unexplained weight loss
  • Fatigue and/or anaemia (pale complexion, weakness and breathlessness)
  • Urine colour changes – dark, rusty, or brown

Keep a lookout for the following giveaways and contact your doctor for further tests whenever you experience:

  • Tiredness. Colon cancer can cause a lack of iron in the body, resulting in anaemia (lack of red blood cells). If you have anaemia, you will most likely be tired and have pale skin.
  • Bleeding. There are many causes of bleeding from your bottom or blood in your poo. Bright red blood may come from haemorrhoids in your back passage. But, it might also be a symptom of colon cancer. Inform your doctor if you have dark red or black blood coming from your stomach or bowel.
  • Change in bowel habits. Inform your doctor if you notice any mysterious shifts in your bowel habits, especially if you are also experiencing bleeding from your back passage. For example, you may have looser stools (diarrhoea) and need to urinate more frequently than usual. Alternatively, you may believe that you are not going to the toilet frequently enough or that you are not completely emptying your bowels.
  • Sudden weight loss. This is a less common symptom than some of the others. Speak to your doctor if you've lost weight and don't know why. You may not want to eat if you are sick, bloated, or do not feel hungry.

Causes of bowel cancer

Usually, bowel cancer develops when healthy cells in the colon undergo DNA mutations.

Healthy cells divide and grow to keep your body functioning normally.

When a cell's DNA is harmed and develops cancer, it continues to divide — even when new cells aren't required. As the cells multiply, they form a tumour.

Cancer cells can spread over time, invading and destroying normal tissue in their path.

The following risk factors may increase your risk of bowel cancer:

  • Age
  • Genes
  • Family History: hereditary non-polyposis colorectal cancer (HNPCC) & familial adenomatous polyposis (FAP)
  • History of Colorectal Cancer or Polyps
  • History of Crohn's disease and severe ulcerative colitis
  • A High-Fat Diet
  • Inflammatory Bowel Syndrome
  • Inactive lifestyle
  • Obesity
  • Diabetes
  • Alcohol
  • Smoking

Bowel cancer prevention

What can you do to reduce the risk of developing bowel cancer?

Doctors advise people to begin colon cancer screening around age 45.

People at a higher risk, such as those with a family history of bowel cancer, should consider asking for screening sooner.

There are several screening options, each with pros and cons. Discuss your options with your doctor during consultations, and you can decide which tests are right for you.

You can reduce your risk of bowel cancer by making the following lifestyle changes:

  • Eat Healthily
  • Quit smoking
  • Limit alcohol
  • Exercise
  • Keep a healthy weight

Bowel cancer screening

Colon cancer is most common in older people but can strike at any age. The most common starting point is polyps, which are tiny, noncancerous (benign) clusters of cells that form inside the colon. Over time, some of these polyps may develop into bowel cancer.

Polyps can be tiny and cause few, if any, symptoms. As a result, doctors advise regular screening tests to help prevent bowel cancer by detecting and removing polyps before they develop into cancer.

To detect bowel cancer cases earlier, everyone aged 60 to 74 who lives in England (and has a GP) is automatically sent a bowel cancer screening home test kit every two years.

If you are 75 or older, you can request a screening kit every two years by calling the free bowel cancer screening helpline (0800 707 60 60).

You collect a small sample of poo with a home test kit and send it to a lab for the screening test. This is examined for trace amounts of blood.

Blood can indicate polyps or bowel cancer. Polyps are bowel growths that can progress to cancer over time.

Genevieve Edwards, Chief Executive of Bowel Cancer UK, told Health Times: “Bowel cancer is treatable and curable especially if diagnosed early. Nearly everyone survives bowel cancer if diagnosed at the earliest stage, but this drops significantly as the disease develops. Early diagnosis really does save lives.  

“GPs see people with bowel concerns every day so there is nothing to be embarrassed about. Being aware of the symptoms and visiting your GP if you are concerned can help increase chances of an early diagnosis. The UK’s bowel screening programme starts at the age of 50 or 60, depending on where you live, with a simple test being sent out to people who are eligible. The FIT (Faecal Immunochemical Test) test looks for hidden blood in poo, and will be sent out automatically if you're registered with a GP and within the screening age range, which can be completed in the privacy of your own home.”

Bowel cancer diagnosis

A variety of tests are used to detect bowel cancer. First, your doctor will perform a physical examination to determine whether you have any abdominal swelling. Then, your doctor will perform a rectal exam to look for any lumps or swelling in the rectum or anus.

Medical professionals might also use the following procedures to diagnose bowel cancer:

  • Immunochemical occult blood test for faeces (iFOBT)
  • Blood test
  • Colonoscopy
  • Sigmoidoscopy
  • MRI
  • A CT scan
  • PET examination

Bowel cancer treatment

According to the National Health Service in the UK (NHS), many treatments are available to help control bowel cancer, including surgery, radiation therapy, and drug treatments such as targeted therapy, chemotherapy, and immunotherapy.

Certain medications have been shown to lower the risk of precancerous polyps or colon cancer.

Some evidence links regular use of aspirin or aspirin-like drugs to a lower risk of polyps and colon cancer.

However, it is unclear what dose and duration of treatment would be required to reduce the risk of colon cancer. In addition, daily aspirin use carries some risks, such as gastrointestinal bleeding and ulcers.

These options are typically reserved for people with an increased risk of colon cancer. However, there is insufficient evidence to recommend these medications to people with a low risk of colon cancer.

If you have a greater risk of colon cancer, speak with your doctor about whether you should take preventive medications.

Living with bowel cancer

Bowel cancer can have various effects on your daily life, depending on the stage of your cancer and the treatment you are receiving.

Here are a few pointers to help to live with bowel cancer:

  • Inform your friends and family; they may be a valuable source of support.
  • Learn about your health; don't try to do too much or overexert yourself, and make time for yourself.
  • Interact with people in similar situations, such as bowel cancer support groups.
  • Research end of life care possibilities.
The content on is provided for informational and educational purposes only and should not be construed as professional medical advice or guidance. Should you need professional medical advice or guidance, you should consult with such a professional in their relevant field. Likewise, you should always seek professional medical advice before starting a diet, exercise regime or course of medication, or introducing or eliminating specific elements from your lifestyle. We strive to write accurate, genuine and helpful content, and all views and opinions expressed within this article are specifically the views of the author.
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