Factors associated with the risk of adenoma recurrence in distal and proximal colon

Colonoscopy may be less effective in preventing cancer in the proximal colon. We evaluated whether risk factors for adenoma recurrence exhibit differential effect on adenoma recurrence by colon subsite.

We examined the association of age, sex, body mass index, smoking status and use of nonsteroidal anti-inflammatory drugs (NSAIDs) on proximal and distal adenoma recurrence among 1,864 participants in the Polyp Prevention Trial. We used multinomial logistic regression models to calculate the relative risk ratios (RRR) and 95% CI.

733 (39.3%) participants had adenoma recurrence (228 distal only, 369 proximal only and 136 synchronous proximal and distal adenoma). When compared to participants without adenoma recurrence, no factor was associated with an increased risk of distal only adenoma recurrence. Age 65-69 years (RRR = 1.47, 95% CI 1.00-2.16), age ≥70 years (RRR = 2.24, 95% CI 1.57-3.20), and male sex (RRR = 1.73, 95% CI 1.32-2.27) were positively associated with proximal only adenoma recurrence. NSAIDs use was associated with a reduced risk of adenoma recurrence by similar magnitude in distal (RRR = 0.78, 95% CI 0.58-1.07) and proximal colon (RRR = 0.77, 95% CI 0.60-1.00).

We did not find any modifiable risk factor that differentially increases proximal as compared to distal adenoma recurrence to be clinically useful for targeted intervention.