# Poster Session I - A101 HOW SOON IS NECESSARY? A SYSTEMATIC REVIEW & META-ANALYSIS OF SURVEILLANCE INTERVALS AFTER RESECTION OF ≥ 3 NON-ADVANCED ADENOMAS

## TL;DR

This study reviews how often patients with multiple small colon polyps should be checked for cancer, finding that shorter check-up intervals reduce cancer risk.

## Contribution

This is the first systematic review and meta-analysis comparing surveillance intervals specifically for patients with ≥3 non-advanced adenomas.

## Key findings

- Shorter surveillance intervals significantly reduce colorectal cancer and advanced adenoma risks.
- A dose-response relationship was observed between surveillance interval length and cancer risk.
- Certainty of evidence was rated as very low due to risk of bias and indirectness.

## Abstract

Extending surveillance intervals for patients with > 3 small non-advanced adenomas (NAAs) is increasingly recommended, yet this trend is supported by systematic reviews using inappropriate comparator groups (polyp-free patients, general population) rather than comparisons of different intervals.

This first systematic review and meta-analysis (SRMA) compares surveillance intervals in adults with a baseline finding of > 3 small NAAs.

This SRMA was conducted to inform the CAG post-polypectomy surveillance guideline. We searched MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials up to March 2025 for randomized controlled trials (RCTs) and cohort studies comparing predefined surveillance intervals (<3 vs. 4–5 years, <5 vs. 6–10 years, <6 vs. 7–10 years, <10 vs. >10 years). Two reviewers independently performed study selection, data extraction, and quality assessment. Primary outcomes were colorectal cancer (CRC) incidence and mortality. Secondary outcomes included CRC stage, adverse events, all-cause mortality, and advanced adenoma (AA) incidence. Pooled risk ratios (RR) with 95% confidence intervals (CI) were calculated with a random-effects model. Heterogeneity was assessed by Chi2 (P < 0.15) and I2 tests (>25%). We assessed the certainty of evidence (CoE) with the GRADE approach.

From 3086 citations, 4 cohort studies (3 retrospective, 1 prospective) were included. No RCTs were identified. A dose-response relationship was observed: shorter surveillance intervals were associated with lower risks of CRC and AA across all comparisons (Table 1). The CoE for all outcomes was very low due to serious risk of bias and serious indirectness.

Shorter surveillance intervals significantly reduce CRC and AA risks in patients with ≥3 small NAAs, supporting intensive surveillance and challenging prolonged intervals. Future research should identify higher-risk subgroups for personalized strategies.

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