How do we screen for bowel cancer?

What is bowel cancer?

Bowel cancer is a catch-all term for any cancers in the colon or rectum - sometimes called colorectal cancer. It affects around 43,000 people a year in the UK and is the fourth most common type of cancer.

The five most common symptoms of bowel cancer:

• Blood in your poo or bleeding from your bottom.

• A persistent and unexplained change in your bowel habits.

• Unexplained weight loss.

• Extreme, unexplained tiredness.

• A pain or lump in your abdomen - general tummy area.

The NHS routinely screens everyone between 60 and 74, and since 2021 has also begun inviting everyone aged 50 to 59.

Faecal immunochemical testing (FIT)

The NHS sends people a home test kit, known as a faecal immunochemical test (FIT). You use the kit to collect a tiny sample of poo.

In the lab, samples are checked for blood, further screening tests will then diagnose whether or not the person has bowel cancer.

Dr Kevin Monahan is a consultant gastroenterologist at St Mark's in London, and was a lead author on essential new guidance for GPs on FIT testing¹.

"Patients are facing significant delays and we're struggling to identify those patients who are most likely to require investigation," he says. "We want to be more accurate in how we can offer investigations because symptoms on their own are a rather crude way of identifying patients with bowel cancer.

"If we add FIT, we have an objective measure that can say, 'These are the people who most likely need to be investigated'. The doctor explains that whilst FIT may not be 100% certain, it is a very good test.

Dr Lisa Wilde, director of research and external affairs at Bowel Cancer UK, says FIT testing is particularly good at ruling out bowel cancer quickly for patients under 50. Only 6% of diagnoses are in people under 50, so although doctors are looking for it, they know it's rare².

"It's entirely possible for a GP to go through their entire career without necessarily seeing a person under 50 with bowel cancer," Dr Wilde explains. "We want bowel cancer ruled out quickly for people, especially in that younger group - which is small but growing."

Anyone can seek a referral if they have noticed one of the symptoms, and people in England aged 58 to 74 can take part in screening without symptoms.

How often are people screened for bowel cancer?

The national bowel cancer screening programme writes to people in the at-risk age group every two years.

Lynch syndrome

Some people are at greater risk of certain types of cancer, including bowel cancer, because they carry a genetic disposition known as Lynch syndrome.

All people who have this syndrome are offered a colonoscopy - camera test to check for colon cancer.

No, bowel cancer screening has not been suspended. After being paused at the start of the COVID pandemic, routine screening had returned across the UK by December 2020³.

Does bowel cancer show up in blood tests?

Yes, some patients might be offered a test to find 'tumour markers' in your blood.

Can a CT scan detect bowel cancer?

Yes, after an endoscopy patients may be recommended a CT scan to further investigate bowel cancer.

How is bowel cancer diagnosed?

Bowel cancer is usually diagnosed after endoscopy.

For information about the bowel cancer screening programme, please contact your local screening service:

• England: 0800 707 6060

• Northern Ireland: 0800 015 2514

• Scotland: 0800 012 1833

• Wales: 0800 294 3370

The Macmillan Support Line can help with clinical, practical and financial information about a cancer diagnosis. Call 0808 808 0000, 8 am-8 pm any day of the week.

The Cancer Research UK nurses line can be reached on 0808 800 4040, Monday to Friday 9 am-5 pm.

1. BSG:Faecal immunochemical testing (FIT).

2. Bowel Cancer UK.

3. National Bowel Cancer Audit.