What you need to know about bowel cancer

What is bowel cancer?

Bowel cancer (also known as colorectal cancer) is a common illness that starts when cells lining the colon or rectum grow out of control. It often develops from small, non‑cancerous growths called polyps. While not all polyps become cancerous, some can turn malignant over several years if they are not detected and removed.

In the UK, bowel cancer is a major health issue - there are over 46,570 new cases each year, making it the fourth most common cancer [1]. It occurs more often in people over 60 and is slightly more common in men than women.

Can bowel cancer be prevented?

While not all cases of bowel cancer can be prevented, evidence suggests that over half may be linked to lifestyle factors that we can influence. This means that making healthier everyday choices can play an important role in reducing risk, alongside attending screening and being aware of symptoms.

Factors linked to a higher risk of bowel cancer include:

• A diet low in fibre
• Eating large amounts of red or processed meat
• Physical inactivity
• Being overweight or obese
• Drinking alcohol regularly
• Smoking

Just as these factors can increase risk, positive changes can help support long‑term bowel health.

The benefits of early detection

Finding bowel cancer early can make treatment simpler and more effective. Regular screening can:

• Catch cancer early: Which means treatment is often more successful.
• Remove polyps: In many cases, polyps can be detected and removed before they turn into cancer.
• Lower your risk: Regular screening has been shown to reduce deaths from bowel cancer by up to 25-30% [2].

Because early bowel cancer often causes no symptoms at all, screening plays a crucial role in protecting health.

Why screening matters

Bowel cancer screening looks for early signs of cancer or pre‑cancerous changes in people who feel well. By picking up problems early, screening helps increase survival rates and reduce the need for more intensive treatment later on.

What screening tests are available?

Several screening tests are available to help detect bowel cancer early:

• Stool Testing (FIT): 
  The Faecal Immunochemical Test (FIT) checks for hidden blood in a stool sample. It is simple to use at home and is sent by post to people aged 60–74 every two years in England. The NHS is gradually expanding the programme to include people aged 50–59. If blood is detected, further tests are arranged.
• Sigmoidoscopy: 
  A sigmoidoscopy uses a flexible tube with a camera to look directly into the lower part of the bowel (the sigmoid colon and rectum), where most cancers are found. Previously used in some areas, sigmoidoscopy is now less commonly part of routine NHS screening, with FIT being the main test.
• Colonoscopy: 
  A colonoscopy uses a thin, flexible tube with a camera to examine the whole bowel. It is usually offered after a positive FIT result or to people at higher risk, such as those with a strong family history of bowel cancer.
• CT Colonography (Virtual Colonoscopy): 
  This scan uses X‑rays to create detailed images of the bowel. It may be offered to people who are unable to have a colonoscopy. If anything unusual is found, a colonoscopy may still be needed.

Recognising the signs and symptoms

Knowing what changes might signal a problem is important. Look out for:

• Changes in bowel movements: Diarrhoea, constipation, or a change in how your stool looks.
• Blood in the stool: This might be visible or hidden.
• Abdominal pain: Persistent discomfort or pain.
• Unexplained weight loss: Losing weight without trying may be a warning sign.

Having these symptoms does not mean you have bowel cancer, but they should always be checked by a healthcare professional.

Taking action

You should consider speaking to your doctor if you:

• Are over 50
• Have a family history of bowel cancer
• Have long‑term bowel conditions such as Crohn’s disease or ulcerative colitis
• Notice persistent bowel symptoms

Taking part in the NHS bowel cancer screening programme is one of the most effective ways to protect your health.

What should you do?

Unless there is a clear reason not to, participating in bowel cancer screening is strongly recommended. If you have symptoms or are at higher risk, your clinician can advise whether you need earlier or more frequent testing.

Bowel cancer is a serious condition, but it is highly treatable when found early. By understanding the risks, recognising symptoms, and making screening a regular part of your healthcare routine, you can take an important step towards protecting your health.

References

1. Bowel cancer statistics, Cancer Research UK, https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/bowel-cancer
2. Bowel cancer screening standards data report 2023-25, Gov.uk, https://www.gov.uk/government/publications/bowel-cancer-screening-annual-report-2023-to-2024/bowel-cancer-screening-standards-data-report-2023-24