Nonsteroidal anti‐inflammatory drugs (NSAID) and aspirin for preventing colorectal adenomas and carcinomas

Abstract

Background

There is evidence from experimental animals studies, prospective and retrospective observational studies that nonsteroidal anti‐inflammatory drugs (NSAIDS) may reduce the development of sporadic colorectal adenomas (CRAs) and cancer (CRC) and may induce the regression of adenomas in familial adenomatous polyposis (FAP).

Objectives

To conduct a systematic review to determine the effect of NSAIDS for the prevention or regression of CRAs and CRC.

Search methods

Randomized controlled trials (RCTs) up to September 2003 were identified.

Selection criteria

NSAIDS and aspirin (ASA) were the interventions. The primary outcomes were the number of subjects with at least one CRA, the change in polyp burden, and CRC. The secondary outcome was adverse events.

Data collection and analysis

Two reviewers independently extracted data and assessed trial quality. Dichotomous outcomes were reported as relative risks (RR) with 95% confidence intervals (CI). The data were combined with the random effects model if clinically and statistically reasonable.

Main results

Nine trials with 150 familial adenomatous polyposis (FAP) and 24,143 population subjects met the inclusion criteria. The interventions included sulindac, celecoxib, or aspirin (ASA). From the combined results of three trials, significantly fewer subjects in the low dose ASA group developed recurrent sporadic CRAs [RR 0.77 (95% CI 0.61, 0.96), (NNT 12.5 (95% CI 7.7, 25)] after one to three years. In another three trials, phenotypic FAP subjects that received sulindac or celecoxib had a greater proportional reduction (range: 11.9% to 44%) in the number of CRAs compared to those in the control group (range: 4.5% to 10%). There was no significant difference for the outcomes of CRC or adverse events in any of the trials.

Authors' conclusions

There was evidence from three pooled RCTs that ASA significantly reduces the recurrence of sporadic adenomatous polyps after one to three years. There is evidence from short‐term studies to support regression, but not elimination or prevention of CRAs in FAP.

Author(s)

Tracey K. Asano, Robin S McLeod

Abstract

Plain language summary

Colorectal (bowel) cancer is common worldwide but is especially prevalent in industrialised countries. Genes, diet and lifestyle all seem to be important in the development of bowel cancer.

Experimental animals studies and observational studies have suggested that nonsteroidal anti‐inflammatory drugs and aspirin may reduce the development of colorectal cancer and recurrence of adenomas in patients with familial adenomatous polyposis (FAP).

The review found some evidence to support the effectiveness of aspirin for reducing the risk of recurrent sporadic colorectal adenomas. Further, there is evidence from short‐term studies to support regression, but not elimination or prevention of colorectal adenomas in FAP with NSAIDs. -The review suggests more research on the long‐term role of NSAIDs.

Author(s)

Tracey K. Asano, Robin S McLeod

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

There is some evidence from the pooled data of three RCTs to support the effectiveness of one to three years of ASA for reducing the risk of recurrent sporadic CRAs. Similarly, there is evidence from short‐term studies to support regression, but not elimination or prevention of CRAs in FAP with NSAIDs.

Implications for research 

More evidence from ongoing RCTs is necessary to establish the long‐term role of NSAIDs for the prevention of CRAs in addition to currently recommended CRC screening strategies for the average risk population or routine surveillance for post‐polypectomy or FAP patients.

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