Association between statin use and risk for keratinocyte carcinoma in the veterans affairs topical tretinoin chemoprevention trial

Abstract

Background: Recent evidence suggests that statins may prevent cancer. Objective: To quantify the association between statin use and the occurrence of keratinocyte carcinoma in high-risk veterans. Design: Cohort study. Setting: 6 Veterans Affairs medical centers. Participants: 1037 participants of the Veterans Affairs Topical Tretinoin Chemoprevention Trial, a randomized, multicenter, double-blind, vehicle-controlled trial of topical tretinoin, 0.1%, for prevention of keratinocyte carcinoma conducted from November 1998 to November 2004. Measurements: Time to first occurrence of keratinocyte carcinoma on the face or ears. Participants using a statin at randomization, according to the Veterans Affairs Pharmacy Benefits Management database, were considered exposed. Study dermatologists conducted physical examinations at baseline and every 6 months during follow-up. The association between statin use at randomization and the outcome was evaluated by using propensity score matching (n = 608) and Cox proportional hazards regression (n = 1037). Results: Among the 1037 participants, 37% used a statin at randomization (n = 397) for a median duration of at least 900 days over a median follow-up of 3.5 years. In the propensity score-matched analysis, statin use at randomization was not associated with keratinocyte carcinoma (rate ratio, 0.92 [95% CI, 0.73 to 1.16]), a finding that was consistent with the estimates derived from the Cox proportional hazards regression (rate ratio, 0.84 [CI, 0.70 to 1.02]). Limitations: The extent of residual confounding is unknown, and the confidence bounds around the measures of association were wide. These data may not be generalizable to lower-risk populations. Conclusion: These data show no conclusive or consistent relationship between long-term statin use and risk for keratinocyte carcinoma. Funding: Department of Veterans Affairs, Agency for Healthcare Research and Quality, American Cancer Society, and National Institutes of Health. © 2009 American College of Physicians.