Topical hydrocortisone, clobetasol propionate, and calcipotriol do not increase photocarcinogenesis induced by simulated solar irradiation in hairless mice.

Topical corticosteroids such as hydrocortisone-17-butyrate (HCB) and clobetasol-17-propionate (CP) and vitamin D(3) derivatives such as calcipotriol (CAL) are widely used to treat psoriasis. The immunosuppressive effects of corticosteroids make their topical use a concern for skin carcinogenicity. Few studies have assessed the effect of topical corticosteroids and topical vitamin D(3) derivatives on photocarcinogenesis induced by ultraviolet radiation. We investigated whether HCB, CP, or CAL can accelerate photocarcinogenesis using simulated solar radiation (SSR). HCB, CP, or CAL was applied topically to the backs of hairless, female, C3.Cg/TifBomTac-immunocompetent mice in 16 groups of 25 mice each. The drugs were applied three times weekly followed by 0, 2, 4, or 6 standard erythema doses (SED) of SSR for 365 days or until death. No change was observed in the time required for tumor development in mice treated with HCB and 2 SED (HCB-2SED) and HCB-6SED. However, the time required for tumor development increased with HCB-4SED treatment. Treatment with CP-2SED did not change the time to onset of the first and second tumor, but all other CP treatments in combination with SSR increased the time. CAL-2SED decreased the time to onset of the first tumor but not of the second and third tumor. CAL-4SED and CAL-6 SED did not change or increased the time to tumor development. Our data indicated that topical administration of HCB and CAL did not alter the photocarcinogenesis of SSR and that topical CP administration had a photoprotective effect. Thus, HCB, CP, and CAL do not increase photocarcinogenesis induced by SSR.