Bowel cancer symptoms, screening and treatment: a clear, kind guide

By the KCK editorial team Medically reviewed by Dr Mohammad Muneeb Khan, MBBS, MRCP (London), MSc Clin Onc, FRCR Last reviewed 18 July 2026 9 min read

The short answer

The main bowel cancer symptoms are a lasting change in your bowel habit, blood in your poo, and tummy pain or bloating. Most people with these signs do not have cancer. But because bowel cancer is very treatable when found early, any change that lasts three weeks or more is worth a word with your GP.

In short

Main symptoms: a lasting change in bowel habit, blood in your poo, tummy pain, bloating, and unexplained weight loss.
Most of these symptoms have harmless causes, such as piles or a change in diet, but a lasting change deserves a check.
Bowel cancer is very treatable when caught early: more than 9 in 10 people survive if found at the earliest stage.
The NHS sends a free home screening kit, the FIT test, to everyone aged 50 to 74 every two years.
General information, not medical advice. Bleeding heavily or in severe pain? Call NHS 111, or 999 in an emergency.

When bowel cancer is diagnosed at the earliest stage, more than 9 in 10 people survive for five years or more. Source: Cancer Research UK.

Bowel cancer is one of the most common cancers in the UK, and it is also one of the most treatable when it is found early. That is why this guide spends as much time on screening and symptoms as on treatment. Reading it is a quietly powerful thing to do.

What are the symptoms of bowel cancer?

The main symptoms of bowel cancer are a change in your normal bowel habit, blood in your poo, tummy pain or bloating, and losing weight without trying. Most people with these symptoms turn out to have a far more common, harmless cause. A change that will not settle is the thing to act on.

Signs worth noticing include:

A change in your bowel habit, such as looser poo, going more often, or constipation
Blood in your poo, or bleeding from your bottom
Tummy pain, discomfort or bloating, especially after eating
A feeling that your bowel does not empty fully
Losing weight without trying, or feeling very tired for no clear reason

Blood in your poo is often caused by piles, and a change in habit can come from a change in diet, stress or a stomach bug. None of that means you should ignore it. If a symptom is new, unexplained, or lasts three weeks or more, please see your GP, even if it feels awkward.

What is bowel cancer, and how common is it?

Bowel cancer is cancer that starts in the large bowel, made up of the colon and the rectum, so it is also called colon cancer, rectal cancer or colorectal cancer. It is one of the most common cancers in the UK. Most cases begin as small growths called polyps, which can be removed before they turn cancerous.

That last point is worth holding on to. Because bowel cancer usually develops slowly from polyps, screening can catch changes early, sometimes before cancer even forms. Few cancers give us that much of a head start.

What causes bowel cancer, and who is at higher risk?

The exact cause is not known, but bowel cancer risk rises with age, diet, weight and family history. Around half of UK bowel cancers are linked to risk factors we can influence, which is unusually hopeful for a common cancer. Having a risk factor is never a diagnosis.

Age, with most cases diagnosed in people over 50
A diet high in red and processed meat, and low in fibre
Being overweight, inactive, or drinking a lot of alcohol
Smoking
A family history of bowel cancer, or an inherited condition such as Lynch syndrome
Long-standing inflammatory bowel disease, such as Crohn's or ulcerative colitis

If bowel cancer runs in your family, or you have a bowel condition, talk to your GP about whether you need checks earlier or more often than the routine screening programme offers.

When should I see my GP about bowel symptoms?

See your GP if you have a change in bowel habit, bleeding, or tummy pain that lasts three weeks or more, or if you feel unusually tired or are losing weight without trying. Bowel symptoms can feel embarrassing to talk about, but your GP has these conversations every day.

Try not to let awkwardness cost you time. Most people who see their GP with these symptoms do not have cancer, and getting checked simply settles the question. If something does need treating, whether it is cancer or something else, finding it sooner almost always makes it easier to deal with.

What is the NHS bowel cancer screening test?

The NHS bowel cancer screening test is a free home kit called the FIT test, which checks your poo for tiny amounts of hidden blood that you cannot see. Everyone registered with a GP is sent one every two years, and the programme is expanding to include everyone from age 50 to 74.

Using the kit takes a couple of minutes at home, and you post it back. A normal result is reassuring, and an abnormal result does not mean you have cancer, it means you are invited for a further test, usually a colonoscopy, to look more closely. Doing the test when it arrives is one of the simplest ways to protect yourself, so please do not leave it in a drawer.

How is bowel cancer diagnosed?

If symptoms or a screening result raise a concern, the main test is a colonoscopy, where a thin camera is used to look inside the bowel and take samples if needed. Further scans then check whether anything found has spread, which doctors call staging.

A FIT test, checking your poo for hidden blood
Colonoscopy, the main test, looking directly inside the bowel
Biopsy, taking a small sample to examine
CT or MRI scans, to check the size of a cancer and whether it has spread

A colonoscopy can feel daunting, but the team does everything to make it comfortable, and it is often the test that catches a problem early enough to treat it simply.

What are the treatments for bowel cancer?

The main treatment for bowel cancer is surgery to remove the affected part of the bowel, sometimes with chemotherapy or radiotherapy as well. The right plan depends on where the cancer is, its stage, and your general health. Many early bowel cancers are treated with surgery alone.

Surgery removes the cancer and a margin of healthy bowel, and is the main treatment for most cases.
Chemotherapy uses medicines to lower the chance of the cancer coming back, or to control advanced cancer.
Radiotherapy is used mainly for cancer in the rectum, sometimes before surgery to shrink it.
Targeted therapy and immunotherapy are options for some advanced bowel cancers.

Some people worry about needing a stoma, a bag to collect waste. Many do not need one, and where a stoma is needed it is often temporary, with excellent support from your team and charities such as Macmillan. Our prevention and living-well guides point to more help, and you can get in touch any time.

What do the stages of bowel cancer mean?

Stage describes how far bowel cancer has grown into the bowel wall and whether it has spread. It is usually given as a number from 1 to 4, where stage 1 is contained in the bowel lining and stage 4 has spread to another organ. Stage is the biggest single factor in the outlook.

Stage	In plain English
Stage 1	Only in the inner layers of the bowel wall. Very treatable, often with surgery alone.
Stage 2	Has grown deeper into the bowel wall, but has not reached the lymph nodes.
Stage 3	Has spread to nearby lymph nodes, usually treated with surgery and chemotherapy.
Stage 4	Has spread to another part of the body, such as the liver or lungs. Treatment aims to control it and keep you well, and can sometimes still cure it.

Even stage 4 bowel cancer can sometimes be cured, particularly when it has spread only to the liver and can be removed. Your team can explain what your stage means for you, which matters far more than the number by itself.

What is the outlook, and can bowel cancer be prevented?

The outlook for bowel cancer is closely tied to how early it is found, and found early it is one of the most survivable cancers. Around half of cases are also linked to things we can influence, so prevention genuinely works here. That combination, screening plus healthy habits, is a real opportunity.

Steps with the strongest evidence behind them:

Do the FIT screening test whenever your kit arrives.
Eat more fibre, from wholegrains, vegetables, fruit and pulses.
Cut down on red and processed meat.
Keep a healthy weight, stay active, and go easy on alcohol.
Stop smoking, with free NHS support if you would like it.

No single habit is a guarantee, and no one who develops bowel cancer is to blame. But stacked together, screening and these steps move the odds a long way, which is the whole idea behind our mission.

Guides like this are free, medically reviewed, and paid for by supporters, not pharma. If yours was useful, there are many ways to help.

Get involved

Common questions

What is usually the first sign of bowel cancer?

There is no single first sign, but a lasting change in bowel habit or blood in your poo are among the most common early symptoms. Tiredness from a low blood count can also be an early clue. Because these signs are usually caused by something harmless, the useful rule is to check anything that lasts three weeks or more.

Is blood in your poo always cancer?

No, and it usually is not. Blood in your poo is far more commonly caused by piles, a small tear, or a stomach upset than by cancer. But because it can occasionally be a warning sign, it is always worth getting checked rather than waiting to see if it settles.

What does bowel cancer poo look like?

There is no single appearance, which is why symptoms matter more than trying to judge by sight. Blood can look bright red or very dark, and poo may become looser or narrower than usual. Rather than diagnosing yourself, mention any lasting change to your GP, who can arrange the right test.

At what age does bowel cancer screening start?

The NHS is lowering the starting age so that everyone from 50 to 74 is offered the FIT home test every two years. If you are older than 74 you can still request a kit, and anyone with symptoms should see their GP at any age rather than waiting for screening.

Is bowel cancer curable?

Very often, yes, especially when it is caught early. More than 9 in 10 people survive when bowel cancer is found at the earliest stage, and even some advanced cases can be cured, particularly when the spread is limited. This is exactly why screening and early checks matter so much.

Can you prevent bowel cancer?

You cannot remove all risk, but around half of UK bowel cancers are linked to factors you can influence. Eating more fibre, cutting red and processed meat, keeping a healthy weight, staying active, drinking less and not smoking all help, and doing the screening test can catch changes before they become cancer.

Sources

Medically reviewed

Dr Mohammad Muneeb Khan — MBBS, MRCP (London), MSc Clinical Oncology, FRCR

Consultant clinical oncologist, NHS England. This guide is general information, not personal medical advice. Always speak to your own clinical team; in an emergency, call 999. Full profile →