[Treatment of precancerous conditions of the skin].

The precancerous skin lesions are defined clinically. Sooner or later they show the tendency to develop into an actual cancer. The most common epithelial precancerous lesion is the actinic keratosis. Sun-exposure for many years and poor pigmentation of the skin predispose for developing actinic keratosis. For the efficient treatment of epithelial precancerous lesions primarily a clear diagnosis is needed. If the diagnosis is not clear a biopsy or excision followed by histological examination is necessary. The treatment modalities for office procedures are: excisional surgery, curettage, electrocoagulation, dermabrasion and cryosurgery. Ionizing radiation in the form of x-rays may be useful for treatment of elder patients with multiple actinic keratosis and large lentigo maligna. Topical chemotherapy (5-Fluorouracil, trichloroacetic-acid) requires good compliance and frequent follow-up. The follow-up of patients with precancerous skin lesions is mainly on the clinical level. These patients should use sun-protective agents.