The effects of aspirin on melanoma are unclear, with studies reporting conflicting results. Data from two periods of the ASPirin in Reducing Events in the Elderly (ASPREE) study; the randomized placebo-controlled trial period examining daily 100 mg aspirin in older adults with a median follow-up of 4.7 years, and the second period, an additional 2 years of observational follow-up, were utilized in this secondary analysis to examine whether aspirin exposure is associated with a reduced cutaneous melanoma incidence. All melanoma cases were adjudicated and Cox proportional hazards models were used to compare incidence between randomized treatment groups. ASPREE recruited 19,114 participants with a median age of 74 years. During the trial period, 170 individuals (76 aspirin, 94 placebo) developed an invasive melanoma, and no significant effect of aspirin was observed on incident melanoma [HR = 0.81; 95% confidence interval (CI), 0.60–1.10]. Including the additional 2 years of observational follow-up (median follow-up of 6.3 years), 268 individuals (119 aspirin, 149 placebo) developed an invasive melanoma, and similar results were observed (HR = 0.81; 95% CI, 0.63–1.03). A reduced number of events was observed with aspirin among females in a subgroup analysis (HR = 0.65; 95% CI, 0.44–0.92); however, the interaction effect with males (HR = 0.92; 95% CI, 0.68–1.25) was nonsignificant (P = 0.17). Our findings from this randomized trial do not provide strong support that aspirin is associated with a reduced risk of invasive melanoma in older individuals. Additional studies are required to further explore this relationship.
Melanoma prevention is an important strategy to improve outcomes and while preventive efforts have largely focused on sun protection, the role of potential chemopreventive agents such as aspirin warrants investigation.