Bowel Cancer Symptoms & Screening

Bleeding from the bottom, blood in stool, changes in bowel habits, ongoing diarrhoea or constipation, and unexplained weight loss.
June 12, 2026

Bowel cancer is one of the most common cancers in the UK, but when detected early, treatment is often more effective and outcomes can be significantly improved. Unfortunately, many people dismiss early symptoms or assume they are caused by less serious digestive conditions.

Understanding the warning signs and knowing when to seek further investigation can play an important role in protecting your long-term health.

What Is Bowel Cancer?

Bowel cancer, also known as colorectal cancer, develops in the colon or rectum. In many cases, it begins as small growths called polyps, which can gradually develop into cancer over time if left untreated.

One of the reasons bowel cancer screening is so important is that polyps can often be detected and removed before they become cancerous.

Common Symptoms of Bowel Cancer

Symptoms can vary from person to person and may develop gradually. In the early stages, some people experience no symptoms at all.

Common signs that should not be ignored include:

  • Blood in your stool
  • Rectal bleeding
  • Persistent changes in bowel habits
  • Ongoing diarrhoea or constipation
  • Abdominal pain or cramping
  • Feeling that your bowel does not fully empty
  • Unexplained fatigue
  • Iron deficiency anaemia
  • Unexplained weight loss

While these symptoms are not always caused by cancer, they should always be assessed by a healthcare professional.

Changes in Bowel Habits to Look Out For

A noticeable change in bowel function can sometimes indicate an underlying problem within the digestive tract.

Warning signs may include:

  • More frequent bowel movements
  • Persistent constipation
  • Alternating constipation and diarrhoea
  • Narrow or ribbon-like stools
  • Difficulty passing stool
  • A feeling of incomplete emptying after using the toilet

If these symptoms persist for several weeks, further investigation may be recommended.

Understanding Blood in Your Stool

Blood in the stool is one of the most recognised symptoms associated with bowel cancer, although it can also occur with haemorrhoids, anal fissures and inflammatory bowel conditions.

The appearance of blood can vary:

Bright Red Blood

Often associated with bleeding lower in the bowel or rectum.

Dark Red Blood

May indicate bleeding higher within the colon.

Black or Tarry Stools

Can suggest bleeding higher in the digestive tract and should be investigated urgently.

Regardless of the amount or colour, any unexplained rectal bleeding should be discussed with a medical professional.

Who Is Most at Risk?

Although bowel cancer can affect adults of any age, certain factors can increase risk.

These include:

  • Being over the age of 50
  • A family history of bowel cancer
  • Previous colon polyps
  • Inflammatory bowel disease
  • Type 2 diabetes
  • Smoking
  • Obesity
  • A diet high in processed or red meat

Some inherited conditions, such as Lynch Syndrome and Familial Adenomatous Polyposis (FAP), can also increase the likelihood of developing bowel cancer.

Why Early Screening Matters

Many bowel cancers develop slowly over several years, often beginning as harmless polyps.

Screening and diagnostic testing can:

  • Detect bowel cancer at an earlier stage
  • Identify precancerous polyps
  • Investigate unexplained symptoms
  • Provide reassurance when symptoms are caused by less serious conditions

Early diagnosis can significantly improve treatment options and outcomes.

How a Colonoscopy Helps Diagnose Bowel Cancer

A colonoscopy is considered one of the most effective methods for examining the large bowel.

During the procedure, a specialist uses a thin flexible camera to inspect the lining of the colon and rectum. This allows them to identify:

  • Polyps
  • Inflammation
  • Bleeding sources
  • Bowel cancer
  • Other abnormalities affecting the digestive tract

If polyps are discovered, they can often be removed during the same procedure, helping to reduce future cancer risk.

Can Bowel Cancer Be Prevented?

While it is not always possible to prevent bowel cancer, lifestyle choices can help lower your risk.

Follow a Healthy Diet

Aim to eat plenty of fruit, vegetables and fibre while limiting processed and red meats.

Stay Physically Active

Regular exercise supports digestive health and helps maintain a healthy weight.

Maintain a Healthy Weight

Excess body fat has been linked to an increased risk of bowel cancer.

Stop Smoking

Smoking increases the risk of numerous cancers, including bowel cancer.

Attend Screening Appointments

Regular screening and prompt investigation of symptoms remain among the most effective ways to detect bowel cancer early.

Book a Private Colonoscopy in Birmingham with Gut Diagnostics

If you are experiencing rectal bleeding, persistent digestive symptoms, changes in bowel habits, or have concerns about your bowel cancer risk, a colonoscopy can provide valuable answers.

At Gut Diagnostics, we offer fast access to private colonoscopy services in Birmingham, helping patients receive expert assessment without lengthy waiting times. Our experienced team provides comprehensive digestive health investigations in a professional and supportive environment.

Contact Gut Diagnostics today to book your consultation and learn more about our private colonoscopy services in Birmingham.

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