Non-melanoma skin cancer and NSAID use in women with a history of skin cancer in the Women's Health Initiative

Objective: Evidence for the effect of non-steroidal anti-inflammatory drugs (NSAIDs) on non-melanoma skin cancer (NMSC) risk is inconsistent. We prospectively examined whether regular, inconsistent, or no/low-use of NSAIDs is associated with lower NMSC risk among 54,728 postmenopausal Caucasian women in the Women's Health Initiative Observational Study enrolled between 1993 and 1998. Methods: Logistic regression models were used to assess odds of NMSC after adjusting for skin type, sun exposure history and indication for NSAID use. Results: There were 7652 incident cases of NMSC (median follow-up: 6.9 years). There was no association between regular NSAID-use and NMSC risk relative to no/low-users. However, in a subgroup analysis of 5325 women with a history of skin cancer (incident NMSC: 1897), odds of NMSC were lower among regular NSAID users whether < 5 years (OR 0.82, 95% CI: 0.70-0.95) or ≥ 5 years (OR 0.82, 95% CI: 0.69-0.98) of use compared to no/low-users. Inconsistent NSAID use and acetaminophen use were not associated with NMSC risk. Conclusion: Overall, NSAID use was not associated with NMSC risk. However, in women with a history of skin cancer, regular NSAID use was associated with 18% lower odds of NMSC. Future studies on potential chemopreventative effects of NSAIDs should focus on subjects with prior history of NMSC.