Intermediate-risk patients with three to four small adenomas should be considered low risk for colorectal cancer screening.

Background And Aim: Intermediate-risk patients following a colorectal cancer screening program may have differential risk of advanced lesions depending on the findings of an index colonoscopy. The aim of the present study was to comparatively assess advanced colorectal neoplasia risk at the first follow-up colonoscopy among the different intermediate-risk subgroups with a focus on patients with three to four adenomas.

Methods: All patients recruited for a baseline screening colonoscopy between 2006 and 2011 were included. Number, size and histopathological characteristics of adenomas were collected. Main outcome was an advanced colorectal neoplasia detection rate (invasive carcinoma or advanced adenoma) at the first follow-up colonoscopy. Low- and high-risk patients were excluded.

Results: Five hundred and sixty-one intermediate-risk patients (63.3% men, mean age: 59.01 ± 6.16 years) underwent indexing and follow-up colonoscopy. By multivariate analysis, three to four adenomas (OR: 3.613 [95% CI: 1.661-7.859], P = 0.001) and adenoma size ≥10 <20 mm (OR: 3.374 [95% CI: 1.618-7.034], P = 0.001) were independent factors associated with advanced colorectal neoplasia. Advanced lesions were detected in 7.66% of cases. Of patients with advanced colorectal neoplasia, 51.16% belonged to the three-to-four-adenoma group and ≥1 of ≥10 <20-mm subgroups (n = 132, 23.53%). These patients demonstrated a higher rate of advanced lesions [OR: 3.886 (95% CI: 2.061-7.325), P < 0.001] than patients with three to four small adenomas of <10 mm (16.67% vs 5.07%, P < 0.001). The association between patients with small adenomas (n = 217, 38.68%) and advanced lesions was not significant (OR: 0.521 [95% CI: 0257-1.056], P = 0.066).

Conclusion: Intermediate-risk patients with three to four small adenomas achieved a very low advanced lesion rate at follow up. Surveillance interval should be lengthened because these patients should be considered low risk.