Incidence of non-melanoma skin cancer in patients treated with psoralen and ultraviolet A therapy

INTRODUCTION: Studies reporting incidences of non-melanoma skin cancer (NMSC) are heterogeneous, depend on the geographic area of the studied population and are often short-term. The aim of this study is to determine the incidence of NMSC in patients treated with oral PUVA therapy in the Mediterranean area. MATERIAL AND METHODS: A retrospective, observational study was carried out with a sample of 234 patients treated with systemic PUVA between 1982 and 1996, carrying out a historical follow-up until May 2017. The incidencedensity rate of CCNM (crude and adjusted) was calculated by direct standardisation. The incidence of CCNM was compared with that reported in the general population in a similar geographical area. RESULTS: 50 neoplasms were diagnosed in 22 patients. The prevalence of CCNM in patients treated with phototherapy was 10.3%. The mean follow-up time was 21 years. The crude-adjusted incidence density rate of CCNM was 554.4-183.9 cases/100,000 treated patients per year. The crude-adjusted incidence density rate of basal cell carcinoma was 352.3-111.2 cases/100.000 patients and of squamous cell carcinoma was 229-77.7 cases /100,000 patients. CONCLUSION: PUVA therapy is associated with an increased risk of CCNM inthe Mediterranean population.