Radiation therapy for extensive actinic keratosis.

Actinic keratosis in the most common premalignant keratotic tumour of sun-exposed skin. A 66-year-old man developed a large actinic keratosis on his scalp, which did not respond to conventional treatment. Fractionated radiotherapy with a cumulative dose of 28 Gy resulted in complete remission without relapse during a 14-month follow-up. In older subjects in whom conventional treatment fails, low-dose fractionated radiation therapy is an effective alternative method.