SKIN CANCERS OR PREMALIGNANT LESIONS OCCUR IN HALF OF HIGH-DOSE PUVA PATIENTS

Although treatment of psoriasis with psoralen and ultraviolet A (PUVA) is associated with a longterm risk of development of cutaneous squamo us cell carcinoma (SCC), the role of PUVA alone is not established, as many patients in reported series had also received treatment with oth er carcinogens, such as superficial X-rays or arsenic. We have recalle d and examined 54 of the 63 patients still alive who have had PUVA tre atment in our department, and who have been exposed to a cumulative WA dose greater than 2000J/cm(2). None of the patients had been treated with superficial X-rays or arsenicals. Ten patients (19%) had develope d SCC, and 25 (46%) had histologically atypical squamous keratoses ari sing at body sites similar to the carcinomas. The patients with SCC we re significantly older at the start of PUVA treatment than those with keratoses alone. None of the 13% of patients without PUVA lentigines h ad keratoses or SCCs. These results show that high-dose PUVA treatment in the U.K., even when given alone, can frequently result in the deve lopment of SCC. Further malignancies are to be expected with continued follow-up of the patients with squamous keratoses. Absence of PUVA le ntigines may be a useful indicator of a lower risk of PUVA malignancy.