Comparative effectiveness of chemopreventive interventions for colorectal cancer: protocol for a systematic review and network meta-analysis of randomised controlled trials

Selective COX-2 inhibitors do not increase gastrointestinal reactions after colorectal cancer surgery: a systematic review and meta-analysis

BACKGROUND

The effectiveness of selective COX-2 inhibitors in preventing colorectal cancer recurrence has been demonstrated, however it is unknown how safe and successful they will be over the long term. As a result, we looked at the efficacy, safety, and consequences of adding COX-2 inhibitors to the treatment plan afterward.

METHODS

In patients with advanced colorectal cancer, we compared the efficacy of celecoxib at two different doses (200 mg twice day and 400 mg twice daily) with placebo. To evaluate the impacts of post-treatment, several datasets from inception to June 2022 were searched. Response rate, illness control rate, and 3-year survival were the main results. And evaluated several safety outcomes, particularly those that were susceptible to adverse events.

RESULTS

The study comprised a total of 9 randomized controlled trials (3206 participants). Celecoxib and rofecoxib doidn't significantly improved the 1-3 year remission rate (OR, 1.57 [95% CI: 0.95-2.57]) and disease control rate (OR, 1.08 [95% CI: 0.99-1.17]). Subgroup analysis of different doses showed that 400 mg of celecoxib significantly improved the response rate (OR, 2.82 [95%CI: 1.20-6.61]). 200 mg celecoxib was not significant (OR, 1.28 [95% CI: 0.66-2.49]). Rofecoxib also did not fully improve disease response rates. Celecoxib at any dose improved 3-year survival (OR, 1.21 [95% CI: 1.02-1.45]). It is important to note that COX-2 inhibitors did not significantly enhance the likelihood of adverse events including gastrointestinal or cardiovascular side effects at any dose.

CONCLUSIONS

For patients with advanced colorectal cancer, a reasonable chemoprevention regimen can include celecoxib 400 mg twice daily.

Very-low-dose aspirin and surveillance colonoscopy is cost-effective in secondary prevention of colorectal cancer in individuals with advanced adenomas: network meta-analysis and cost-effectiveness analysis

BACKGROUND

Individuals with advanced colorectal adenomas (ACAs) are at high risk for colorectal cancer (CRC), and it is unclear which chemopreventive agent (CPA) is safe and cost-effective for secondary prevention. We aimed to determine, firstly, the most suitable CPA using network meta-analysis (NMA) and secondly, cost-effectiveness of CPA with or without surveillance colonoscopy (SC).

METHODS

Systematic review and NMA of randomised controlled trials were performed, and the most suitable CPA was chosen based on efficacy and the most favourable risk-benefit profile. The economic benefits of CPA alone, 3 yearly SC alone, and a combination of CPA and SC were determined using the cost-effectiveness analysis (CEA) in the Malaysian health-care perspective. Outcomes were reported as incremental cost-effectiveness ratios (ICERs) in 2018 US Dollars ($) per quality-adjusted life-year (QALY), and life-years (LYs) gained.

RESULTS

According to NMA, the risk-benefit profile favours the use of aspirin at very-low-dose (ASAVLD, ≤ 100 mg/day) for secondary prevention in individuals with previous ACAs. Celecoxib is the most effective CPA but the cardiovascular adverse events are of concern. According to CEA, the combination strategy (ASAVLD with 3-yearly SC) was cost-saving and dominates its competitors as the best buy option. The probability of being cost-effective for ASAVLD alone, 3-yearly SC alone, and combination strategy were 22%, 26%, and 53%, respectively. Extending the SC interval to five years in combination strategy was more cost-effective when compared to 3-yearly SC alone (ICER of $484/LY gain and $1875/QALY). However, extending to ten years in combination strategy was not cost-effective.

CONCLUSION

ASAVLD combined with 3-yearly SC in individuals with ACAs may be a cost-effective strategy for CRC prevention. An extension of SC intervals to five years can be considered in resource-limited countries.

Efficacy and safety of celecoxib on the incidence of recurrent colorectal adenomas: a systematic review and meta-analysis

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.

Efficacy and safety of chemopreventive agents on colorectal cancer incidence and mortality: systematic review and network meta-analysis

Background

Various interventions have been tested as primary prevention of colorectal cancers (CRC), but comprehensive evidence comparing them is absent. We examined the effects of various chemopreventive agents (CPAs) on CRC incidence and mortality.

Methods

We did a network meta-analysis based on a systematic review of randomized controlled trials (RCTs) that compared at least one CPA (aspirin, antioxidants, folic acid, vitamin B6, vitamin B12, calcium, vitamin D, alone or in combination) to placebo or other CPA in persons without history of CRC. Several databases were searched from inception up to March 2017. Primary outcomes were early and long-term CRC incidence and mortality.

Results

Twenty-one RCTs comprising 281,063 participants, 9 RCTS comprising 160,101 participants, and 7 RCTs comprising 24,001 participants were included in the network meta-analysis for early risk of CRC incidence, long-term risk of CRC incidence and mortality, respectively. For early CRC incidence, no CPAs were found to be effective. For long-term CRC incidence and mortality, aspirin was the only intervention that showed protective effects with potential dose-dependent effects (risk ratio [RR], 0.74 [95% CI, 0.57–0.97] for high-dose [≥325 mg/day] and RR, 0.81 [95% CI, 0.67–0.98] for very-low-dose [≤100 mg/day]). Similar trend was found for mortality (RR, 0.43 [95% CI, 0.23–0.81] for low-dose [>100–325 mg/day] and RR, 0.65 [95% CI, 0.45–0.94] for very-low-dose). However, in net clinical benefit analysis, when combining risk estimates on mortality from CRC, cardiovascular disease, and pooled risk estimates of major gastrointestinal bleeding, low-dose aspirin provided the highest net survival gain (%) of 1.736 [95% CI, 1.010–2.434].

Conclusion

Aspirin at the dose range of 75–325 mg/day is a safe and effective primary prevention for long-term CRC among people at average risk. None of the other CPAs were found to be effective. There may potentially be differential effects among various doses of aspirin that needs further investigation.

Effects of aspirin and non-aspirin nonsteroidal anti-inflammatory drugs on the incidence of recurrent colorectal adenomas: a systematic review with meta-analysis and trial sequential analysis of randomized clinical trials

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.

Effects of calcium on the incidence of recurrent colorectal adenomas: A systematic review with meta-analysis and trial sequential analysis of randomized controlled trials

BACKGROUND

Protective effects of calcium supplementation against colorectal adenomas have been documented in systematic reviews; however, the results have not been conclusive. Our objective was to update and systematically evaluate the evidence for calcium supplementation taking into consideration the risks of systematic and random error and to GRADE the evidence.

METHODS

The study comprised a systematic review with meta-analysis and trial sequential analysis (TSA) of randomized controlled trials (RCTs). We searched for RCTs published up until September 2016. Retrieved trials were evaluated using risk of bias. Primary outcome measures were the incidences of any recurrent adenomas and of advanced adenomas. Meta-analytic estimates were calculated with the random-effects model and random errors were evaluated with trial sequential analyses (TSAs).

RESULTS

Five randomized trials (2234 patients with a history of adenomas) were included. Two of the 5 trials showed either unclear or high risks of bias in most criteria. Meta-analysis of good quality RCTs suggest a moderate protective effect of calcium supplementation on recurrence of adenomas (relative risk [RR], 0.88 [95% CI 0.79-0.99]); however, its effects on advanced adenomas did not show statistical significance (RR, 1.02 [95% CI 0.67-1.55]). Subgroup analyses demonstrated a greater protective effect on recurrence of adenomas with elemental calcium dose ≥1600 mg/day (RR, 0.74 [95% CI 0.56-0.97]) compared to ≤1200 mg/day (RR, 0.84 [95% CI 0.73-0.97]). No major serious adverse events were associated with the use of calcium, but there was an increase in the incidence of hypercalcemia (P = .0095). TSA indicated a lack of firm evidence for a beneficial effect. Concerns with directness and imprecision rated down the quality of the evidence to "low."

CONCLUSION

The available good quality RCTs suggests a possible beneficial effect of calcium supplementation on the recurrence of adenomas; however, TSA indicated that the accumulated evidence is still inconclusive. Using GRADE-methodology, we conclude that the quality of evidence is low. Large well-designed randomized trials with low risk of bias are needed.

Effects of chemopreventive agents on the incidence of recurrent colorectal adenomas: a systematic review with network meta-analysis of randomized controlled trials

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.

Comparative effectiveness of chemopreventive interventions for colorectal cancer: protocol for a systematic review and network meta-analysis of randomised controlled trials

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer worldwide and is associated with substantial socioeconomic burden. Despite considerable research, including numerous randomised controlled trials (RCTs) and systematic reviews assessed the effect of various chemopreventive interventions for CRC, there remains uncertainty regarding the comparative effectiveness of these agents. No network meta-analytic study has been published to evaluate the efficacies of these agents for CRC. Therefore, the aim of this study is to summarise the direct and indirect evidence for these interventions to prevent CRC in average-high risk individuals, and to rank these agents for practical consideration.

METHODS

We will acquire eligible studies through a systematic search of MEDLINE, EMBASE, the Cochrane Central Registry of Controlled Trials, CINAHL plus, IPA and clinicaltrials.gov website. The Cochrane Risk of Bias Tool will be used to assess the quality of included studies. The primary outcomes are the incidence of CRC, the incidence/recurrence of any adenoma or change in polyp burden (number or size). Quantitative synthesis or meta-analysis will be considered. We will also construct a network meta-analysis (NMA) to improve precision of the comparisons among chemo-preventive interventions by combining direct and indirect evidence. The probability of each treatment being the best and/or safest, the number-needed-to-treat [NNT; 95% credible interval (CrIs)], and the number-needed-to-harm (NNH; 95% CrIs) will be calculated to provide measures of treatment efficacy. The GRADE approach will be used to rate the quality of evidence of estimates derived from NMA.

RESULTS

This protocol has been registered (registration number: CRD42015025849) with the PROSPERO (International Prospective Register of Systematic Reviews). The procedures of this systematic review and NMA will be conducted in accordance with the PRISMA-compliant guideline. The results of this systematic review and NMA will be submitted to a peer-reviewed journal for publication.

CONCLUSIONS

To the best of our knowledge, this study will be the first NMA to identify the comparative effectiveness of interventions for the prevention of CRC. The results of our study will update evidence for chemoprevention of CRC, identify key areas for future research, and provide a framework for conducting large systematic reviews involving indirect comparisons.