Is UVB treatment of psoriasis safe? A study of extensively UVB-treated psoriasis patients compared with a matched control group.

The aim of the study was to investigate whether or not extensively UVB-treated psoriatics ran a greater risk of developing skin cancer than did controls. The 85 most extensively UVB-treated psoriasis patients during recent decades have been investigated with regard to premalignant and malignant skin lesions and compared with a population matched for age, sex, and geographic region. The prevalence of persons who had or had had premalignant/malignant skin lesions was 5.9% (n = 85) in the psoriasis group, vs. 10.1% in the control group (n = 338). This difference is not statistically significant and the confidence limits are such that it is unlikely that the psoriasis patients treated in the past have an increased prevalence of premalignant and malignant skin lesions. A multiple regression analysis has been conducted among the controls, showing a correlation between premalignant/malignant skin changes and advanced age and outdoor occupations. No such correlation was found for the factors: sex, skin type, or travel to southern latitudes.