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Background: Celecoxib has previously been shown to be effective in reducing recurrent colorectal adenomas, but its long-term effects are unknown. In addition, safety issues are of major concern. Therefore, we examined the efficacy and safety of celecoxib as a chemopreventive agent along with its posttreatment effect. Methods: We performed a meta-analysis based on a systematic review of randomized controlled trials (RCTs) comparing celecoxib at various doses (400 mg once daily, 200 mg twice daily, and 400 mg twice daily) vs placebo in persons with history of colorectal adenomas. Several databases were searched from inception up to April 2018. Long-term follow-ups of RCTs were also included to evaluate posttreatment effect. Primary outcome was the incidence of recurrent colorectal adenomas. Various safety outcomes were evaluated, especially cardiovascular (CV) events. Risk–benefit integrated analyses were also performed. Results: A total of three RCTs (4,420 patients) and three post-trial studies (2,159 patients) were included in the analysis. Use of celecoxib at any dose for 1–3 years significantly reduced the incidence of recurrent advanced adenomas (risk ratio, 0.42 [95% CI, 0.34–0.53]) and any adenomas (0.67 [95% CI, 0.62–0.72]) compared with placebo. Subgroup analysis on different dosing suggested a greater effect with 400 mg twice daily. However, celecoxib 400 mg twice daily significantly increased the risk of serious adverse (1.2 [95% CI, 1.0–1.5]) and CV events (3.42 [95% CI, 1.56–7.46]), while celecoxib at 400 mg/day, especially with once daily dosing, did not increase CV risk (1.01 [95% CI, 0.70–1.46]). Analysis of post-trial studies indicated that the treatment effect disappeared (1.15 [95% CI, 0.88–1.49]) after discontinuing celecoxib for >2 years. Conclusion: Celecoxib 400 mg once daily dosing could potentially be considered as a viable chemopreventive option in patients with high risk of adenomas but with low CV risk. Long-term trials on celecoxib at a dose of ≤400 mg either once or twice daily are warranted. [ABSTRACT FROM AUTHOR]

Background: Beneficial effects of aspirin and non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) against recurrent colorectal adenomas have been documented in systematic reviews; however, the results have not been conclusive. Uncertainty remains about the appropriate dose of aspirin for adenoma prevention. The persistence of the protective effect of NSAIDs against recurrent adenomas after treatment cessation is yet to be established.Methods: Our objective was to update and systematically evaluate 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. Retrieved trials were evaluated using Cochrane risk of bias instrument. Meta-analytic estimates were calculated with random-effects model and random errors were evaluated with trial sequential analysis (TSA).Results: In patients with a previous history of colorectal cancer or adenomas, low-dose aspirin (80-160 mg/day) compared to placebo taken for 2 to 4 years reduces the risk of recurrent colorectal adenomas (relative risk (RR), 0.80 [95% CI (confidence interval), 0.70-0.92]). TSA indicated a firm evidence for this beneficial effect. The evidence indicated moderate GRADE quality. Low-dose aspirin also reduces the recurrence of advanced adenomas (RR, 0.66 [95% CI, 0.44-0.99]); however, TSA indicated lack of firm evidence for a beneficial effect. High-dose aspirin (300-325 mg/day) did not statistically reduce the recurrent adenomas (RR, 0.90 [95% CI, 0.68-1.18]). Cyclooxygenase-2 (COX-2) inhibitors (e.g. celecoxib 400 mg/day) were associated with 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]); however, this association did not persist and there was a trend of an increased risk of recurrent adenomas observed 2 years after the withdrawal.Conclusion: Our findings confirm the beneficial effect of low-dose aspirin on recurrence of any adenomas; however, effect on advanced adenomas was inconclusive. COX-2 inhibitors seem to be more effective in preventing recurrence of adenomas; however, there was a trend of an increased risk of recurrence of adenomas observed after discontinuing regular use. [ABSTRACT FROM AUTHOR]

Background: Protective effects of several chemopreventive agents (CPAs) against colorectal adenomas have been well documented in randomized controlled trials (RCTs); however, there is uncertainty regarding which agents are the most effective. Methods: We searched for RCTs published up until September 2016. Retrieved trials were evaluated using risk of bias. We performed both pairwise analysis and network meta-analysis (NMA) of RCTs to compare the effects of CPAs on the recurrence of colorectal adenomas (primary outcome). Using NMA, we ranked CPAs based on efficacy. Results: We identified 20 eligible RCTs enrolling 12,625 participants with a history of colorectal cancer or adenomas who were randomly assigned to receive either a placebo or one of 12 interventions. NMA using all trials demonstrated that celecoxib 800 mg/day (relative risk [RR] 0.61, 95% confidence interval [CI] 0.45-0.83), celecoxib 400 mg/day (RR 0.70, 95% CI 0.55-0.87), low-dose aspirin (RR 0.75, 95% CI 0.59-0.96) and calcium (RR 0.81, 95% CI 0.69-0.96) were significantly associated with a reduction in the recurrence of any adenomas. NMA results were consistent with those from pairwise meta-analysis. The evidence indicated a high (celecoxib), moderate (low-dose aspirin) and low (calcium) Grading of Recommendations, Assessment, Development and Evaluation (GRADE) quality. NMA ranking showed that celecoxib 800 mg/day and celecoxib 400 mg/day were the best CPAs, followed by low-dose aspirin and calcium. Considering advanced adenoma recurrence, only celecoxib 800 mg/day and celecoxib 400 mg/day were demonstrated to have a protective effect (RR 0.37, 95% CI 0.27-0.52 vs RR 0.48, 95% CI 0.38-0.60, respectively). Conclusion: The available evidence from NMA suggests that celecoxib is more effective in reducing the risk of recurrence of colorectal adenomas, followed by low-dose aspirin and calcium. Since cyclooxygenase-2 (COX-2) inhibitors (eg, celecoxib) are associated with important cardiovascular events and gastrointestinal harms, more attention is warranted toward CPAs with a favorable benefit-to-risk ratio, such as low-dose aspirin and calcium. [ABSTRACT FROM AUTHOR]