Photochemotherapy utilizing 8-methoxypsoralen and ultraviolet A (PUVA) is a highly effective and widely used treatment for psoriasis and other dermatoses. Several studies in the United States and Europe have demonstrated that long-term oral PUVA therapy is associated with an increased occurrence of skin cancer.
Although the carcinogenic potency of PUVA in Japanese patients may be lower than that in Western populations, skin cancer can develop associated with carcinogenic risk factors. The carcinogenecity of concomitant use of oral cyclosporin A and photochemotherapy is the focus of interest.
In order to find out PUVA-induced malignant and pre-malignant skin conditions, an adequate knowledge of such lesions and risk factors is needed. PUVA lentigines and PUVA keratoses are observed in long-term PUVA therapy, but the carcino-genic potential of these lesions is still unclear. [Skin Cancer (Japan) 2003; 18: 148-155]