Colorectal Cancer: Symptoms, Screening, Prevention and Early Diagnosis

Colorectal cancer, also known as bowel cancer, includes cancer of the colon and rectum. It is one of the most common cancers in the UK and worldwide.

The reassuring message is that bowel cancer is often highly treatable and potentially curable when detected early.

This guide explains bowel cancer symptoms, screening (FIT test), early-onset colorectal cancer, risk factors, prevention, and survival rates.

Why colorectal (bowel) cancer matters

• Around 42,000 people are diagnosed each year in the UK
• It is the 4th most common cancer in the UK
• It remains a leading cause of cancer-related deaths, largely due to late diagnosis

Global perspective (last 5–7 years)

• USA: Rising cases in younger adults
• Europe: High incidence across multiple countries
• Australia: High detection rates but improving survival
• India & Middle East: Lower incidence historically, but rapidly increasing trends, particularly in urban populations

👉 A key emerging issue is early-onset colorectal cancer (under 50 years)

Early-onset colorectal cancer: a growing concern

There has been a clear increase in bowel cancer in people under 50 across the UK, USA, and Europe.

Key points:

• Often diagnosed later due to delayed recognition
• Symptoms may be mistaken for IBS or haemorrhoids
• Requires greater awareness among patients and clinicians

👉 Age alone should not be used to dismiss persistent bowel symptoms

Symptoms of colorectal (bowel) cancer

Many patients have no symptoms in early stages, which is why screening is important.

Common bowel cancer symptoms:

• Rectal bleeding (fresh blood or darker stools)
• Persistent change in bowel habit (diarrhoea, constipation, or both)
• Abdominal pain, bloating, or discomfort
• Unexplained weight loss
• Iron deficiency anaemia
• Feeling of incomplete bowel emptying

👉 These symptoms are common and often due to benign conditions, but should be assessed if persistent.

Who is at risk of colorectal cancer?

Age-related risk:

• Over 60 years → highest risk
• 50–59 years → increasing risk
• Under 50 years → rising incidence

Other risk factors:

• Family history of bowel cancer
• Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
• Diet high in processed/red meat
• Obesity and physical inactivity
• Smoking and alcohol
• Type 2 diabetes

Bowel cancer screening in the UK (FIT test)

The NHS bowel cancer screening programme uses the FIT test (Faecal Immunochemical Test):

• Offered from age 50–74
• Detects microscopic blood in stool
• If positive → referral for colonoscopy

Why screening is important:

• Detects cancer at an earlier stage
• Identifies polyps before they become cancer

👉 Screening significantly improves survival

What is a colonoscopy?

A colonoscopy is the most accurate test for diagnosing bowel cancer.

• Direct visualisation of the colon
• Polyps can be removed during the procedure
• Biopsies can be taken
• Usually performed under light sedation

👉 Learn more:

• Colonoscopy: https://www.theoxfordgastroenterologist.co.uk/colonoscopy/
• Endoscopy services: https://www.theoxfordgastroenterologist.co.uk/endoscopy/

Stages of colorectal cancer and survival rates

Outcomes depend strongly on stage at diagnosis.

Approximate 5-year survival:

• Stage 1: ~90–95%
• Stage 2: ~75–85%
• Stage 3: ~50–70%
• Stage 4: ~10–15%

👉 This highlights the importance of early detection and timely investigation

Can colorectal cancer be prevented?

While not all cases are preventable, risk can be reduced.

Lifestyle measures:

• Maintain a healthy weight
• Exercise regularly
• Eat a high-fibre diet (fruit, vegetables, whole grains)
• Reduce processed and red meat
• Stop smoking
• Limit alcohol

Medical prevention:

• Removal of polyps during colonoscopy
• Surveillance in high-risk patients
• Monitoring in inflammatory bowel disease

When should you seek medical advice?

You should consider medical assessment if you have:

• Rectal bleeding
• Persistent change in bowel habit
• Iron deficiency anaemia
• Unexplained weight loss
• Ongoing abdominal symptoms
• Family history of bowel cancer

👉 Early reassurance is important, but so is not missing an underlying diagnosis

Private consultation and rapid access

At my practice, patients can access:

• Consultant-led assessment
• Rapid access to colonoscopy where appropriate
• Evidence-based, proportionate investigation
• Continuity of care

👉 Arrange an appointment:
https://www.theoxfordgastroenterologist.co.uk/appointments/

👉 Learn more about your consultant:
https://www.theoxfordgastroenterologist.co.uk/about/

👉 View consultation fees:
https://www.theoxfordgastroenterologist.co.uk/fees/

👉 Contact the clinic:
https://www.theoxfordgastroenterologist.co.uk/contact-us/

Frequently Asked Questions (FAQs)

What are the first symptoms of colorectal cancer?

Common symptoms include rectal bleeding, a change in bowel habit, abdominal discomfort, iron deficiency anaemia, weight loss, or a sensation of incomplete bowel emptying. These symptoms are often not due to cancer but should be assessed if persistent.

Can young adults get bowel cancer?

Yes. Early-onset colorectal cancer is increasing in people under 50. Persistent symptoms should not be ignored because of age.

What is the FIT test?

The FIT test is a stool test that detects small amounts of blood not visible to the eye. It is used in NHS screening and in assessing symptoms.

Does a positive FIT test mean cancer?

No. A positive result means further investigation is needed, usually a colonoscopy.

What is the best test for bowel cancer?

Colonoscopy is the most accurate test because it allows direct examination of the bowel lining and enables biopsies or removal of polyps.

Can bowel cancer be prevented?

Risk can be reduced through healthy lifestyle choices and participation in screening. Removal of polyps during colonoscopy also reduces risk.

Is colorectal cancer curable?

When detected early, colorectal cancer is often highly treatable and may be curable. Outcomes are significantly better with early diagnosis.

Key References (evidence-based)

• Cancer Research UK – Bowel Cancer Statistics (UK)
• NHS England – Bowel Cancer Screening Programme
• American Cancer Society (2023–2025 updates)
• GLOBOCAN (WHO/IARC global cancer data)
• Siegel RL et al., CA Cancer Journal for Clinicians (2023–2024)
• European Society for Medical Oncology (ESMO Guidelines)
• Australian Institute of Health and Welfare (AIHW)
• Lancet Oncology Commission on Colorectal Cancer
• Indian Council of Medical Research (ICMR Cancer Registry)
• Middle East Cancer Consortium (MECC)