Veettil SK, et al. - The persistence of the beneficial effects of aspirin and non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) against recurrent colorectal adenomas had been determined. Findings suggested that in patients with a previous history of colorectal cancer or adenomas, aspirin and cyclooxygenase-2 (COX-2) inhibitors reduced the risk of recurrence of colorectal adenomas. However, in case of advanced adenomas their protective effect was inconclusive. COX-2 inhibitors appeared to be more effective in preventing recurrence of adenomas but were associated with important cardiovascular events and gastrointestinal harms. In addition, the protective effect of these agents seemed not persisting and there might even be an increased incidence of recurrent adenomas after their withdrawal.

Methods

• Researchers sought to update and systematically assess the evidence for aspirin and other NSAIDs on the incidence of recurrent colorectal adenomas taking into consideration the risks of random error and to appraise the quality of evidence using GRADE (The Grading of Recommendations, Assessment, Development and Evaluation) approach.
• Analysis of retrieved trials was performed using Cochrane risk of bias instrument.
• They calculated meta-analytic estimates with random-effects model and determined random errors with trial sequential analysis (TSA).

Results

• Low-dose aspirin (80–160 mg/day) vs placebo taken for 2 to 4 years reduced the risk of recurrent colorectal adenomas in patients with a previous history of colorectal cancer or adenomas(relative risk (RR), 0.80 [95% CI (confidence interval), 0.70–0.92]).
• Firm evidence was gained with TSA suggesting this beneficial effect.
• In this study, the evidence indicated moderate GRADE quality.
• The recurrence of advanced adenomas also declined with low-dose aspirin (RR, 0.66 [95% CI, 0.44–0.99]); however, TSA indicated lack of firm evidence for a beneficial effect.
• No statistical reduction in the recurrent adenomas was observed with high-dose aspirin (300–325 mg/day) (RR, 0.90 [95% CI, 0.68–1.18]).
• A significant decrease in the recurrence of both adenomas (RR, 0.66 [95% CI, 0.59–0.72]) and advanced adenomas (RR, 0.45 [95% CI, 0.33–0.57]) was observed with cyclooxygenase-2 (COX-2) inhibitors (e.g. celecoxib 400 mg/day); however, this association did not persist and there was a trend of an increased risk of recurrent adenomas observed 2 years after the withdrawal.