PUVA and cancer: a large-scale epidemiological study.

There is concern about the long-term carcinogenic effects of psoralen and ultraviolet A radiation (PUVA) therapy for treatment of skin disorders. A study of 4799 Swedish patients (2343 males, 2056 females; mean age at first treatment 45.3 years, range 6-93; mean follow-up 6.9 years males, 7.2 years females) who received PUVA between 1974 and 1985 showed a dose-dependent increase in the risk of squamous cell cancer of the skin. Male patients who had received more than 200 treatments had over 30 times the incidence of squamous cell cancer found in the general population. Significant increases (p less than 0.05) were also found in the incidences of respiratory cancer in males and females, pancreatic cancer in males, and kidney and colonic cancer in females. This study confirms previous reports of a dose-dependent increase in the incidence of squamous cell cancer in patients treated with PUVA.