Some studies have demonstrated that 5-aminosalicylic acid (5-ASA) is associated with a reduced risk of colorectal cancer (CRC) in inflammatory bowel disease (IBD).
However, more recent population-based studies suggest no protective association.
Dr Geoffrey Nguyen and colleagues from Canada conducted a systematic review that focused on non-referral studies to reassess the role of 5-ASA for this indication.
The team searched MEDLINE, EMBASE, and the Cochrane databases for studies of non-referral populations that assessed the association between 5-ASA use for at least 1 year, and colorectal neoplasia between 1966 and 2011, and conducted a quantitative meta-analysis.
The team identified 4 observational studies that fulfilled inclusion criteria.
|The sensitivity analysis yielded a pooled adjusted odds ratio of 0.8|
|American Journal of Gastroenterology|
The pooled adjusted odds ratio was 0.95, but there was moderate heterogeneity.
The research team performed a sensitivity analysis that included a fifth study in which 5-ASA use was only for a minimum of 3 months.
The sensitivity analysis yielded a pooled adjusted odds ratio of 0.8.
A series of sensitivity analyses in which each of the 4 studies was excluded one at a time did not show any significant change in the overall pooled odds ratio.
The research team conducted a separate meta-analysis of 9 clinic-based studies, which, in contrast, yielded a pooled odds ratio of 0.6.
Dr Nguyen's team concludes, "Our meta-analysis yielded inconsistent results that were dependent on the inclusion of either non-referral or clinic-based populations."
"Based on non-referral studies, there does not seem to be a protective effect of 5-ASA on colorectal cancer in IBD."
"However, heterogeneity among these studies limits their interpretation."