Background and objective: We investigated the effect of nonsteroidal anti-inflammatory drug (NSAID) use on stage of colon cancer and presence of distant metastases at diagnosis.
Methods: Cases of incident colon cancer diagnosed between 1981 and mid-1995 were selected from the Saskatchewan Cancer Registry. Cases with more extensive cancer at diagnosis were compared with cases with less extensive cancer (characterized using the Dukes system). NSAID exposure was assessed using the Saskatchewan Prescription Drug Plan database.
Results: Compared with non-users in the same period, nonmetastatic cancer was found to be less extensive in those with low NSAID use (odds ratio [OR] 0.67, 95% confidence interval [CI] 0.53-0.87) and high NSAID use (OR 0.55, 95%CI 0.36-0.84) during the 6 to 10 year periods preceding diagnosis, regardless of the cut-off used to define "more extensive cancer." NSAID use in the 2 to 5 year periods was also found to protect (although not statistically significantly) against the occurrence of distant metastasis.
Conclusion: Results are consistent with the hypothesized mechanism of the action of NSAIDs, but confounding by healthy lifestyle cannot be ruled out.