Aspirin for the primary prevention of skin cancer: A meta-analysis

Skin cancer is one of the most common cancers worldwide. There are three major skin cancer types: basal cell carcinoma, squamous cell carcinoma and malignant melanoma. General risk factors for skin cancer include fair skin, a history of tanning and sunburn, family history of skin cancer, exposure to ultraviolet rays and a large number of moles. The incidence of skin cancer has increased in the USA in recent years. Aspirin intake is associated with chemoprotection against the development of a number of types of cancer. However, whether aspirin intake can reduce the risk of development of skin cancer is unclear. The present meta-analysis of available human studies is aimed at evaluating the association between aspirin exposure and the risk of skin cancer. All available human observational studies on aspirin intake for the primary prevention of skin cancer were identified by searching MEDLINE (Pubmed), BIOSIS, EMBASE, Cochrane Library and China National Knowledge Infrastructure prior to March 2013. The heterogeneity and publication bias of all studies were evaluated using Cochran's Q and I² statistics, followed by a random-effect model where applicable. The pooled data were analyzed by odds ratios (ORs) and 95% confidence intervals (CIs). A total of eight case-control and five prospective cohort studies from 11 publications were selected for this analysis. There was no evidence of publication bias in these studies. Statistical analyses of the pooled data demonstrated that that a daily dose of 50-400 mg aspirin was significantly associated with a reduced risk of skin cancers (OR, 0.94; 95% CI, 0.90-0.99; P=0.02). Stratification analysis indicated that the continual intake of low dose aspirin (≤150 mg) reduced the risk of developing skin cancer (OR, 0.95; CI, 0.90-0.99; P=0.15) and that aspirin intake was significantly associated with a reduced risk of non-melanoma skin cancers (OR, 0.97; CI, 0.95-0.99; P=0.22). Overall, these findings indicated that aspirin intake was associated with a reduced risk of developing skin cancer. However, more well-designed randomized controlled trials to measure the effects of aspirin intake are required to confirm this.