Variations in the Investigation of Colorectal Cancer-related Symptoms in Australian Primary Care

Background: Colorectal cancer-related symptoms are commonly seen in primary care. Understanding variations in symptom management is crucial for timely care. Aim: To examine diagnostic testing patterns for gastrointestinal symptoms associated with colorectal cancer in primary care. Design and Setting: Retrospective cohort study using linked primary care data of patients aged ≥40 years presenting with colorectal cancer-related symptoms between 2008 and 2022. Methods: We assessed the proportion of patients receiving diagnostic actions, including medications, pathology, imaging, colonoscopy or specialist referral. We examined differences in testing by socioeconomic status and subsequent colorectal cancer diagnosis. Results: Among 70,107 patients, 378 (0.5%) were diagnosed with colorectal cancer within 12 months. Abdominal pain (32%) and diarrhoea (21%) were the most common symptoms. No investigation or treatment occurred in 20% (change in bowel habit) to 50% (constipation and diarrhoea) of patients. Medication-only management was highest for diarrhoea (11%) and constipation (23%). Blood or imaging tests were most frequent for abdominal pain (36%) and abdominal mass (41%). Colonoscopy or specialist referral was highest for rectal bleeding (67%) and change in bowel habit (60%). Investigation likelihood increased with multiple symptoms or repeat visits (OR 3.40, 95% CI: 3.16–3.65; p < 0.001). Patients aged over 80 were significantly less likely to be investigated or referred (OR 0.53, 95% CI: 0.50–0.55; p < 0.001), while those from more advantaged areas were more likely to be investigated (OR 1.45, 95% CI: 1.38–1.53; p < 0.001). Conclusion: Substantial variation in investigating colorectal cancer-related symptoms may contribute to inequities in diagnostic outcomes.