Nonsteroidal anti-inflammatory drugs (NSAIDs) may protect against skin cancer, according to a study published online December 18 in the Journal of Investigative Dermatology.
NSAID use has been associated with lowered risk for colon, lung, breast, and prostate cancers, but evidence for preventing skin cancer has been inconclusive. Chiho Muranushi, PhD, from the School of Population Health, University of Queensland, Brisbane, Australia, and colleagues conducted a meta-analysis of published studies probing the effects of aspirin, nonaspirin NSAIDs, and use of any NSAIDs on preventing squamous cell carcinoma (SCC).
SCC is a prevalent form of skin cancer for which fair-skinned individuals are most susceptible. NSAIDs (including aspirin, ibuprofen, and naproxen) inhibit cyclooxygenase-2 (COX-2), which catalyzes biosynthesis of prostaglandin E2, a mediator of inflammation. COX-2 is overproduced in SCC in response to chronic exposure to ultraviolet radiation.
The researchers considered nine studies: five case–control, three cohort, and one randomized controlled. The studies reported results for aspirin, nonaspirin, and all NSAIDs.
The metaanalysis indicated significantly reduced risks for SCC among individuals who used nonaspirin NSAIDs (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.78 – 0.94) and among users of any NSAIDs (OR, 0.82; 95% CI, 0.71 – 0.94) compared with people who did not use the drugs. The association was strongest in individuals who had a history of actinic skin tumors or keratinocyte cancers.
Aspirin users showed a reduced risk (OR, 0.88; 95% CI, 0.75 – 1.03) of developing SCC, but with borderline statistical significance. Only the randomized controlled trial revealed a dose–response relationship, for aspirin.
The researchers conclude that use of nonaspirin NSAIDs significantly reduces the risk of developing SCC by 15% and that use of any such drugs does so by 18%. The authors note that the topical NSAID diclofenac is approved to treat actinic keratoses and that the results of the meta-analysis “raise the possibility that oral aspirin or non-aspirin NSAIDs could be used as chemopreventive agents for cutaneous SCC also.”
Limitations of the meta-analysis include the fact that only six of the examined studies were considered high quality, and the chosen studies used different dose units.
The researchers have disclosed no relevant financial relationships.
J Invest Derm. Published online December 18, 2014. Abstract