Photocarcinogenic Risk Associated With Narrowband UV-B Phototherapy: An Epidemiologic Study in a Tertiary Care Hospital.

BACKGROUND: The risk of skin cancer in patients treated with narrowband (NB) UV-B phototherapy is not well understood. Although experimental studies have shown that there is a risk, clinical studies have not detected an increased incidence of cancer following treatment. The aim of this study was to determine the incidence of nonmelanoma skin cancer (NMSC) in patients treated with NB UV-B phototherapy at a tertiary care hospital in the Mediterranean area.

MATERIAL AND METHODS: We conducted a retrospective chart review of 474 patients who received whole-body NB UV-B phototherapy at our hospital between 2002 and 2016 and identified those diagnosed with NMSC during follow-up. We calculated the corresponding crude and standardized incidence rates and compared these with rates in the general population in a similar geographic area.

RESULTS: Of the 474 patients, 193 (40.7%) were men and 281 (59.3%) were women. The mean (SD) follow-up period was 5.8 (3) years. The prevalence of NMSC at the end of the study period was 1.9% and the standardized incidence was 108.3 cases per 100 000 patient-years. The SIR of 1.9 in the study group was not significantly different from that of the general population. The number of patients who needed to be treated with NB UV-B phototherapy for 1 case of NMSC to occur was 1900.

CONCLUSION: NB UV-B phototherapy does not appear to be associated with an increased risk of NMSC.