What Is Bowel Cancer? Do You Know the Symptoms?

Dr Joseph Nightingale
1 day ago
6 min read

Senior couple with grey hair sitting on a bench

Bowel cancer, or colorectal cancer, is a type of cancer that starts in your large intestine (colon). Around 40,000 new colorectal cancers are diagnosed each year in the UK.

Like all cancers, if caught early, it has a much more positive prognosis. Cancers gradually spread over time, becoming harder to treat. Identifying the early signs of colon cancer can significantly improve the prognosis, leading to complete remission in some individuals.

In this guide we'll cover:

What Bowel Cancer is and How it Starts
Early Symptoms and Warning Signs of Bowel Cancer
The Importance of Early Detection of Bowel Cancer
How Doctors Test for Bowel Cancer
How Bowel Cancer is Treated
Bowel Cancer Prevention Diet and Lifestyle Tips
Get a Bowel Cancer Stool Test with Health Klinix
Frequently Asked Questions About Bowel Cancer Symptoms

What is Bowel Cancer? And How Does It Start?

Bowel cancer is also called colorectal cancer. It occurs when abnormal cells in the bowel begin to divide and grow in an uncontrolled way. It can affect anywhere along the large bowel, which is made up of the colon and rectum.

At first, the symptoms of bowel cancer are mild or non-existent. However, as the cancer continues to grow, it will begin to invade the surrounding tissues or organs and can spread to other parts of the body. As it affects normal function, you may begin to notice the initial symptoms.

Early Symptoms and Warning Signs of Bowel Cancer

Early symptoms of bowel cancer can be subtle or even absent, which is why people sometimes miss it. You may notice:

Changes in bowel habit. Going more often or less often, constipation, diarrhoea, or both are all common initial symptoms, especially if they last longer than 3 weeks.
Blood in your stool. Bright red blood often occurs from the lower bowel. If the blood is darker or black, it occurs higher up. However, it can also be due to haemorrhoids, so it’s important to get checked.
Abdominal discomfort or pain. Ongoing cramping, bloating, or discomfort can occur.
Unexplained fatigue or weakness. Feeling tired all the time is common. It’s often due to iron deficiency anaemia from slow blood loss.
Unexplained weight loss. Gradually losing weight without trying can be another sign.

If you experience one mild symptom that’s short-lived, it’s unlikely to be bowel cancer. But if you experience multiple or persistent symptoms, it’s sensible to book a GP appointment. These symptoms don’t always mean cancer, but persistent or worsening changes should never be ignored.

The Importance of Early Detection of Bowel Cancer

Catching bowel cancer early offers the best hope of treating it successfully. During the initial stages, the cancer is usually small and hasn’t spread. That increases the potential treatment options, including surgery to remove the cancer entirely.

In England, around 90% of people with bowel cancer survive for five years or more when diagnosed at the early stage. Sadly, that falls to 11% of people when diagnosed at the latest stage.

Even if the cancer has spread, the sooner it is detected, the more your doctor can do to minimise the complications.

How Do Doctors Test for Bowel Cancer

If your GP suspects you’ve got bowel cancer, they might refer you to a specialist. They will perform a physical exam, pressing on your abdomen or performing a rectal exam to feel for any lumps or polyps.

A colonoscopy is often used to visually inspect the bowel. This involves inserting a narrow tube with a camera on the end into the bowel. The specialist can identify any potential problems, taking biopsies for analysis. It’s the gold standard for diagnosis.

Colonoscopy vs FIT Test for Bowel Cancer Detection

A faecal immunochemical test (FIT) is a common screening test for bowel cancer. The NHS routinely sends these tests to people aged between 50 and 74 years old. It tests for a tiny amount of blood in the stool. If positive, you may be invited for a colonoscopy to confirm if there is any problem. The test is not diagnostic. It’s a screening tool.

A colonoscopy is a more invasive procedure. It’s reserved for people with symptoms or a positive FIT. During the procedure, the clinician can see signs of cancer, polyps, or inflammation, removing polyps to help prevent cancer and taking biopsies. It’s highly accurate and has a small risk of complications.

Feature	FIT Test	Colonoscopy
Type	Screening	Diagnostic
Invasiveness	Non-invasive	Invasive
Location	Performed at home	Performed in a clinical setting
What it detects	Occult (hidden) blood in stool	Structural abnormalities (e.g. polyps, cancer)
Accuracy	Moderate	High
Therapeutic use	No	Yes (e.g., polyp removal, biopsy)

How is Bowel Cancer Treated

Treatment for bowel cancer depends on the stage and type of the disease. If the cancer is still localised to the bowel and nearby structures, surgery may be used to remove the tumour or the affected section of bowel.

In some cases, the bowel can be reconnected. In others, a colostomy may be required, where part of the bowel is brought through the abdominal wall to allow waste to exit into a stoma bag.

Radiotherapy, chemotherapy, or targeted medications may be given before or after surgery. These treatments can help shrink the tumour prior to surgery or reduce the risk of recurrence by destroying any remaining cancer cells.

If the cancer has spread to other parts of the body (metastatic disease), treatment is usually focused on systemic therapies such as chemotherapy, immunotherapy, targeted therapies, or a combination of these. Surgery may still be considered in certain cases, depending on the extent and location of the spread.

Bowel Cancer Prevention Diet and Lifestyle Tips

Bowel cancer is partially linked to our diet and lifestyle. By altering certain factors, you can reduce your risk of developing the condition.

You can try:

Avoiding processed foods, especially processed meats (e.g., hot dogs, sausages, or deli meats)
Eating a more plant-based diet
Reducing your intake of red meat
Quitting smoking
Losing weight if you’re overweight or obese
Lowering your stress levels
Exercising daily

The NHS will also send you a screening test every two years between the ages of 50 and 74. Don’t ignore it. Always send it back on time to help catch bowel cancer early.

Get a Bowel Cancer Stool Test with Health Klinix

If you’ve got symptoms or just want a bit of reassurance, a FIT stool test is a simple place to start. The test from Health Klinix checks for hidden blood in your stool — one of the earliest signs of bowel cancer — and can be done quickly at home.

There’s no need for appointments or invasive procedures, and you’ll get clear results with guidance on what to do next. It’s not a diagnosis, but it helps you decide if further testing is needed. If something feels off, it’s worth checking. You can order your Health Klinix test kit online in just a few minutes.

Order your test

Frequently Asked Questions About Bowel Cancer Symptoms

What is the difference between bowel cancer symptoms and IBS?

Bowel cancer and IBS (irritable bowel syndrome) have several symptoms in common — changes in bowel habit and fatigue. However, IBS does not typically cause blood in the stool and does not worsen over time.

Either way, it’s best to see a doctor if you have any of these symptoms.

What are the main causes and risk factors of bowel cancer?

Colon cancer is often caused by genetic mutations, either inherited or acquired. Risk factors include being over age 50, a history of colon polyps or bowel diseases, and a family history of colon cancer.

What are the survival rates for bowel cancer by stage?

Bowel cancer survival rates decline as the cancer progresses. Currently, the 5-year survival rates are:

Stage 1 — ~90%
Stage 2 — ~85%
Stage 3 — 65%
Stage 4 — 10%

Is there a link between high red meat consumption and increased bowel cancer risk factors?

Yes, high consumption of red and processed meat is linked to an increased risk of bowel cancer. Studies showed that high consumption of red meat increases risk by 28%, and a high consumption of processed meat increases risk by 20%.

Is there a genetic factor to bowel cancer?

Yes, there are genetic factors linked to bowel cancer. People with conditions like Lynch syndrome and familial adenomatous polyposis are at increased risk of developing the disease. Bowel cancer is also more common in people with a family history of the condition.