Risk evaluation of UVB therapy for psoriasis: comparison of calculated risk for UVB therapy and observed risk in PUVA-treated patients.
A descriptive dose-response model is presented to evaluate the long-term risk with respect to non-melanoma skin cancer associated with UVB therapy. The model is based on the results of animal dose-response studies and epidemiological data. A number of factors that influence the risk associated with therapy are evaluated: annual dose applied, solar exposure, therapeutic period, age at start of therapy. Shielding from therapeutic exposures of the skin areas that normally receive the most sun exposure could effectively reduce the risk. The model calculations were compared with observational data, as far as available. The calculated risk corresponded within the limits of statistical error with observed long-term risk of UVB therapy in Sweden; as far as there was a deviation, the model calculations tended to over-estimate the risk. A comparison of the model prognoses for UVB therapy with the observed risk among PUVA-treated patients in the USA shows a much higher observed risk for squamous cell carcinoma among the PUVA-treated patients.
D000328:Adult; D000367:Age Factors; D000368:Aged; D000818:Animals; D002280:Basal Cell Carcinoma / Q000209:etiology; D002294:Carcinoma, Squamous Cell / Q000209:etiology; D004307:Dose-Response Relationship, Radiation; D005069:Evaluation Studies as Topic; D006801:Humans; D051379:Mice; D008875:Middle Aged; D011701:PUVA Therapy; D011565:Psoriasis / Q000188:drug therapy / Q000532:radiotherapy*; D012306:Risk; D013472:Sunlight; D014467:Ultraviolet Therapy