Evaluating the necessity of colonoscopy in patients under 40 with rectal bleeding: insights from a large-scale retrospective analysis.

Purpose: Bleeding per rectum (BPR) is a common clinical presentation, and colonoscopy is the gold standard for evaluating patients aged ≥ 45 years. However, its role in younger patients remains unclear. This study evaluated the appropriateness of colonoscopy in patients < 40 years of age who presented with BPR.

Methods: This retrospective observational study was conducted over 10 years, including 3422 patients aged 18-40 years who underwent colonoscopy for BPR. The cohort was divided into two age groups: younger (aged 18-30 years) and older (31-40 years). The patients' baseline characteristics, colonoscopy findings, and histopathological results were analyzed.

Results: Hemorrhoids were the most common finding (48%), with a higher prevalence in younger age groups (50.7%). Polyps were detected in 12.5% of patients, with 1.75% having advanced adenoma polyps (AAP) and 1.3% diagnosed with colorectal cancer (CRC). A family history of CRC/AAP was significantly associated with increased CRC risk (adjusted OR 6.35, 95% CI 2.24-18.02, p = 0.001) in explorative logistic regression analysis.

Conclusion: AAP and CRC were detected in a small but significant proportion of patients, particularly among those aged 18-30 years. The detection of significant lesions in this age group highlights the need for targeted colonoscopy based on specific risk factors such as family history and clinical presentation. Future research should prioritize the creation of targeted assessment models to improve clinical decision making in this context.