Skin cancer and psoralen plus UVA: a retrospective study of 106 patients exposed to a great number of PUVA treatments

INTRODUCTION: The benefits of PUVAtherapy in many dermatological affections are well known. Its carcinogenic role in the long term has been assessed varyingly in American and European series. OBJECTIVE: The aim of this study was to assess the role of PUVA in the onset of cancers of the skin. METHODS: Retrospective study of patients presenting with psoriasis and followed-up in the phototherapy unit of the Michallon Hospital in Grenoble since 1976 and having received more than 150 sessions of PUVA. The parameters studied were: age, gender, phototype, age at the time of the first irradiation, type of phototherapy administered, total number of sessions, concomitant treatments, administration of retinoids and the appearance of skin cancers with the interval before their onset after the first session, their localization and their histological type. RESULTS: One hundred six patients were retained among the 152 who replied to the inclusion criteria. Having died or been lost to follow-up, forty-six patients were excluded. Fourteen patients had presented at least one cutaneous tumor with a total number of 35. Excluding the keratoacanthomas, 13 patients had a non-melanic cutaneous cancer with a total number of 32 tumors. Ten out of the 14 were phototype III, 3 were phototype II and one was phototype IV. Nine out of 14 had received PUVAtherapy alone and 5 PUVAtherapy and broad spectrum UVB. The number of sessions of PUVA received in all the cases was more than 200 (220 to 780), corresponding to a total dose of UVA comprised between 1460 and 3882 Joules. The delay before onset of the tumors varied from 6 to 27 years after the first PUVAtherapy. The mean age at the time of the first irradiation was of 50.2 years (14-75 years). The mean duration of phototherapy was of 10 years (2.23 years).