Risk of total metachronous advanced neoplasia after detection of proximal hyperplastic polyps, adenomas, and their combination.

Background and study aims: Recent research has identified an association between proximal sessile serrated lesions (SSLs) and an increased risk of advanced metachronous neoplasia (TMAN), with no significant impact from distal SSL. This study aimed to assess the risk of TMAN at follow-up colonoscopy after detecting proximal hyperplastic polyps (HP), adenomas, or their combination at the initial colonoscopy.

Methods: Medical records from patients who underwent colonoscopies in 2014 and 2015 were reviewed. The primary outcome was the presence of TMAN (advanced adenomas or high-risk SSL) at follow-up, based on the presence of proximal HP, adenomas, or their combination during the index colonoscopy.

Results: Out of 2014 patients screened, 764 were included in the final analysis (44.1% male; mean age 63 years; median follow-up of 3.46 years). Patients with both proximal HPs and adenomas during the initial colonoscopy had a significantly higher risk of developing TMAN compared with patients with adenomas and distal HP or adenomas alone (30.5% vs 19%; HR = 1.87; 95% CI, 1.3-2.7). Additionally, a combination of proximal HPs and adenomas posed a higher risk of TMAN than proximal HP alone (30.5% vs 13.9%; HR = 3.6; 95% CI, 1.4-9.5). No significant difference in TMAN risk was observed between patients with adenomas alone versus proximal HP (19.1% vs 13.9%; HR = 1.8; 95% CI, 0.73-4.4).

Conclusion: The presence of both proximal HPs and adenomas significantly increases the risk of TMAN compared with adenomas or HPs alone, highlighting the need for further studies to evaluate the effect of these variables on postcolonoscopy CRC.