Skin carcinomas and treatment with photochemotherapy (PUVA)

A 3 1/2-year follow-up study of 198 patients treated with photochemotherapy (PUVA) revealed a total of 18 carcinomas developed in 11 patients. There were 12 basal cell carcinomas and 6 squamous cell carcinomas, localized mainly on non-sun-exposed areas. Furthermore 9 actinic keratoses were diagnosed in 8 patients. All patients with carcinomas had been exposed to at least one of the following possible risk factors; ionizing radiation, methotrexate (MTX), arsenic, topical nitrogen mustard, or had a history of skin carcinoma previous to PUVA therapy. No significant differences in accumulated UVA dose existed between patients with carcinoma or keratosis and patients without tumours. A subgroup of 38 psoriatics previously treated with MTX was compared with a control group of 101 psoriatics treated with MTX--but never with PUVA. The control group was matched for sex, age and presence of the risk factors: ionizing radiation, arsenic and history of carcinoma. The carcinoma incidence in the PUVA-MTX group was 9% and in the control group 11%. The difference was not significant (p = 0.9).