Dietary factors in the prevention and treatment of nonmelanoma skin cancer and melanoma.

BACKGROUND The endogenous antioxidant system of the skin scavenges reactive oxygen species and combats ultraviolet induced oxidative skin damage. Supporting this cutaneous defense system with topical or oral antioxidants may provide a successful strategy for the treatment and prevention of skin cancer. OBJECTIVE Review evidence regarding treatment and prevention of melanoma and nonmelanoma skin cancers through dietary and topical antioxidants, vitamins, and herbal supplements. METHODS Literature review. RESULTS Review of the literature demonstrates that the administration of synthetic retinoids has not proved beneficial for otherwise healthy patients with nonmelanoma skin cancer. Selenium supplementation has reduced the incidence of several internal malignancies but not of nonmelanoma skin cancer. Synergistic use of beta-carotene with vitamins C and E has demonstrated prophylaxis against reactive oxygen radicals involved in nonmelanoma skin cancer and reduced sunburn reactions significantly. 1,25-dihydroxyvitamin D3 analog CB1093 has demonstrated promise as a therapeutic agent in the regression of the early stages of melanoma in specific cell lines. CONCLUSION Delivery of exogenous antioxidants in combination appears to be a more successful strategy for enhancing the cutaneous antioxidant system than the administration of isolated antioxidants alone. Vitamin D analogs may have a role in the medical therapy of melanoma. However, avoiding exposure to ultraviolet light appears to be the only true panacea against the development of melanoma and NMSC.