Topical tretinoin in actinic keratosis and basal cell carcinoma.

In several studies between 1962 and 1978, topical tretinoin was proved capable of producing complete regression of actinic keratosis and basal cell carcinoma. But because its efficacy is not comparable to that of other modalities, topical tretinoin is currently used only as an adjunct to topical 5-fluorouracil in the treatment of actinic keratosis. One recent report found topical tretinoin ineffective in the chemoprevention of actinic keratosis. Although the oral synthetic retinoids isotretinoin and etretinate have been used in the prevention and treatment of cutaneous malignancy, the potential exists for chronic toxicity from the prolonged systemic therapy that appears necessary for maintaining the chemopreventive effect. For this reason, it may be appropriate to study further the preventive as well as therapeutic effects of topical tretinoin and other retinoids for actinic keratosis and skin cancer. If they prove safe and effective, the use of topical retinoids in the prevention and treatment of cutaneous tumors may be the most significant clinical application of these drugs.