What are the key symptoms and risk factors for colorectal cancer that I should screen for in my patients?

For patients in General Practice, key symptoms and risk factors for colorectal cancer that should prompt further consideration or referral include a combination of specific signs, age, lifestyle, and medical history NICE CKS,NICE CKS.

Key Symptoms to be Aware Of:

• Changes in bowel habits: This is particularly relevant for patients aged 60 and over, or for adults under 50 when combined with other unexplained symptoms like rectal bleeding, abdominal pain, weight loss, or iron-deficiency anaemia NICE CKS.
• Rectal bleeding: Unexplained rectal bleeding in patients aged 50 and over is a significant symptom NICE CKS. For adults under 50, rectal bleeding combined with unexplained abdominal pain, changes in bowel habits, weight loss, or iron-deficiency anaemia warrants attention NICE CKS.
• Abdominal pain: Unexplained abdominal pain, especially when combined with weight loss in patients aged 40 and over, is a concern NICE CKS.
• Unexplained weight loss: This symptom, particularly with abdominal pain in patients aged 40 and over, or with rectal bleeding and other symptoms in adults under 50, should be noted NICE CKS.
• Iron deficiency anaemia: In patients aged 60 and over, or in adults under 50 with rectal bleeding and other symptoms, this requires investigation NICE CKS.
• Rectal or abdominal mass: The presence of either of these should prompt consideration for a suspected cancer pathway referral NICE CKS,NICE NG12.
• Occult blood in faeces: A positive quantitative faecal immunochemical test (FIT) in specific age and symptom groups, or occult blood in faeces in patients aged 60 and over, indicates a need for referral NICE CKS. Primary care teams should be aware that FIT thresholds differ for symptomatic investigation versus screening NICE CKS.

Key Risk Factors:

• Age: The NHS Bowel Cancer Screening Programme invites individuals from age 50 onwards NICE CKS. Specific age thresholds are also crucial for symptom-based referrals, such as 40, 50, and 60 years depending on the symptom combination NICE CKS.
• Lifestyle Factors: Promoting a healthy lifestyle can help reduce the risk of bowel cancer NICE CKS. This includes maintaining a healthy weight, consuming a diet rich in non-starchy vegetables, fruit, pulses, and whole grains, while minimising red and avoiding processed meats NICE CKS. Limiting or avoiding alcohol, avoiding smoking, and engaging in regular physical activity are also important NICE CKS.
• Family History: A family history of colorectal cancer in a first-degree relative, especially if diagnosed under 50 years of age, increases risk NICE CG118.
• Inflammatory Bowel Disease (IBD): Patients with ulcerative colitis (excluding proctitis alone) or Crohn's colitis involving more than one segment of the colon are at increased risk and may require colonoscopic surveillance NICE CG118. The level of risk (low, intermediate, high) depends on factors like disease extent, inflammation activity, presence of post-inflammatory polyps, and family history NICE CG118.
• Adenomas: A history of adenomas also increases risk, and surveillance guidelines exist for these patients NICE CG118.

While national screening programmes are in place for average-risk adults Moore & Aulet 2017Wolf et al. 2018Geneve et al. 2019, primary care plays a vital role in promoting uptake of bowel screening and advising patients that screening is not 100% effective NICE CKS. Patients should be advised to seek urgent medical review if symptoms develop, even if they have recently participated in screening NICE CKS. Negative screening results should not deter investigation of symptomatic patients NICE CKS.