Age and Sex Adenoma Detection Rates in Colonoscopy and Optimization of Screening Age: A Retrospective Analysis.

Background: This study aimed to contribute to the ongoing debate regarding the optimal age to initiate colorectal cancer (CRC) screening by evaluating adenoma detection rates (ADRs) across different age and sex groups and to explore whether national screening guidelines should be revised in line with international trends. Methods: In this single-center, retrospective observational study, 1216 average-risk patients who underwent colonoscopy between January and December 2024 were analyzed. The patients were stratified into three age groups: Group 1 (40-44 years), Group 2 (45-49 years), and Group 3 (50-54 years). ADR, advanced neoplasia detection rate (ADNR), ADR by sex, Boston Bowel Preparation Scale (BBPS) score, and withdrawal times were evaluated. Patients with a history of polypectomy, family history of CRC, incomplete colonoscopy, or inadequate bowel preparation (BBPS score <6) were excluded. Group comparisons were performed using Chi-square or Fisher's exact tests, with P < .05 considered statistically significant. Results: Overall ADR and ADNR were 20.8% and 2.6%, respectively. ADRs by group were 7.6%, 15.8%, and 18.9% in Groups 1, 2, and 3, respectively. A significant difference was found between Groups 1 and 2 (P = .032) but not between Groups 2 and 3 (P = .55). ADR was significantly higher in males (30.2%) than in females (13.1%; P < .001). ADNR was also higher in males (3.7%) than in females (1.8%; P = .048). All patients had withdrawal times >6 minutes. Conclusion: ADR significantly increased from age 45, supporting the potential need to lower the CRC screening age and consider sex-specific strategies. Further prospective multicenter studies are warranted.