PUVA treatment and skin cancer: A follow-up study.

Altogether 525 PUVA-treated psoriatics were re-examined. The mean follow-up period since the beginning of PUVA therapy was 2.1 years (range 1-3.6 years). In 107 cases (20%) the total UVA dose was below 100 J/cm2 and in 20 (4%) over 1000 J/cm2. During PUVA treatment or at re-examination of 14 of the 525 patients (3%) were found to have skin lesions suspected of being malignant. A total of 23 biopsies were taken and in one case a basal-cell carcinoma was histologically verified. This had almost certainly been present before the beginning of the PUVA therapy. Two other patients, both previously treated with methotrexate, had reversible lesions with Bowenoid histology. Both these patients had received a total UVA dose of more than 1000 J/cm2. The incidence of skin carcinomas in the present PUVA treated series was lower than that in hospitalized psoriatics treated with regimens other than PUVA and was not higher than the incidence in the age-matched general population in Finland.