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 ¹,².

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 ².
• Rectal bleeding: Unexplained rectal bleeding in patients aged 50 and over is a significant symptom ². For adults under 50, rectal bleeding combined with unexplained abdominal pain, changes in bowel habits, weight loss, or iron-deficiency anaemia warrants attention ².
• Abdominal pain: Unexplained abdominal pain, especially when combined with weight loss in patients aged 40 and over, is a concern ².
• 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 ².
• Iron deficiency anaemia: In patients aged 60 and over, or in adults under 50 with rectal bleeding and other symptoms, this requires investigation ².
• Rectal or abdominal mass: The presence of either of these should prompt consideration for a suspected cancer pathway referral ²,⁴.
• 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 ². Primary care teams should be aware that FIT thresholds differ for symptomatic investigation versus screening ¹.

Key Risk Factors:

• Age: The NHS Bowel Cancer Screening Programme invites individuals from age 50 onwards ¹. Specific age thresholds are also crucial for symptom-based referrals, such as 40, 50, and 60 years depending on the symptom combination ².
• Lifestyle Factors: Promoting a healthy lifestyle can help reduce the risk of bowel cancer ¹. 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 ¹. Limiting or avoiding alcohol, avoiding smoking, and engaging in regular physical activity are also important ¹.
• Family History: A family history of colorectal cancer in a first-degree relative, especially if diagnosed under 50 years of age, increases risk ⁵.
• 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 ⁵. The level of risk (low, intermediate, high) depends on factors like disease extent, inflammation activity, presence of post-inflammatory polyps, and family history ⁵.
• Adenomas: A history of adenomas also increases risk, and surveillance guidelines exist for these patients ⁵.

While national screening programmes are in place for average-risk adults (Moore and Aulet, 2017; Wolf et al., 2018; Geneve et al., 2019), primary care plays a vital role in promoting uptake of bowel screening and advising patients that screening is not 100% effective ¹. Patients should be advised to seek urgent medical review if symptoms develop, even if they have recently participated in screening ¹. Negative screening results should not deter investigation of symptomatic patients ¹.