A randomized double-blind placebo-controlled trial of oral aspirin for protection of melanocytic nevi against UV-induced DNA damage

DNA damage plays a role in ultraviolet (UV)-induced melanoma. We previously showed that aspirin (ASA) can suppress prostaglandin-E2 (PGE2) and protect melanocytes from UV-induced DNA damage in mice, and suggested that taking ASA before acute sun exposure may reduce melanoma risk. We conducted a prospective randomized placebo-controlled trial to determine if orally administered ASA could suppress PGE2 in plasma and nevi and protect nevi from UV-induced DNA damage. After obtaining plasma and determining the minimal erythemal dose (MED) in 95 subjects at increased risk for melanoma, they were randomized to receive a daily dose of placebo, 81 mg ASA, or 325 mg ASA, in double-blind fashion for one month. After this intervention, one nevus was irradiated (dose = 1 or 2 MED) using a solar simulator. One day later, MED was re-determined, a second plasma sample was obtained, and the UV-irradiated nevus and an unirradiated nevus were removed. ASA metabolites were detected in the second plasma sample in subjects in the ASA arms. There were no significant differences in the pre- and post-intervention MED between those patients receiving ASA and placebo. Significantly reduced PGE2 levels were detected in plasma (second vs. first samples) and in nevi (both unirradiated and UV-treated) in subjects receiving ASA compared to placebo. Comparing UV-treated nevi from the ASA and placebo cohorts, however, did not reveal significant reductions in CD3-cell infiltration or 8-oxoguanine and cyclobutane pyrimidine dimers. Thus ASA did not effectively protect nevi from solar-simulated UV -induced inflammation and DNA damage under the conditions examined.