Nonsurgical treatments for skin cancer: retinoids and alpha-interferon.

Retinoids, the natural and synthetic analogs of vitamin A, and alpha-interferon have been used effectively in the treatment of certain cutaneous premalignancies and malignancies. Retinoids have shown impressive activity against premalignant disorders of the skin (actinic keratoses, keratoacanthoma, epidermodysplasia verruciformis) and of other epithelial sites (oral leukoplakia, cervical dysplasia). In established basal cell skin cancers, topical retinoid treatment has produced a complete response rate of 33%, and systemic retinoids have produced an objective response rate of 51%. In advanced squamous cell skin cancers, systemic retinoids have produced a response rate of over 70%. Intralesional alpha-interferon has produced impressive responses and systemic alpha-interferon has produced a 50% objective response rate in basal and squamous cell carcinoma. Retinoid therapy and alpha-interferon have produced modest overall results in melanoma, although striking individual responses have been reported. In cutaneous T-cell lymphoma, which is notably refractory to chemotherapy, retinoids and alpha-interferon have produced responses in 60%+ and 70%+ of cases, respectively. Retinoids and alpha-interferon, either alone or in combination, offer exciting prospects for primary and neoadjuvant therapy for advanced malignancy. Retinoids also show promise as relatively nontoxic preventive and adjuvant therapy. Researchers should focus on integrating these drugs with other biological response modifiers, differentiation agents, and cytotoxic drugs for treating advanced malignancy.