Cutaneous carcinogenic risk evaluation in 375 patients treated with narrowband-UVB phototherapy: A 15-year experience from our Institute.

BACKGROUND: Narrowband-ultraviolet B (NB-UVB) is widely used for the treatment of several dermatological diseases. A cutaneous carcinogenic effect has been hypothesized, but not proved. METHODS: We retrospectively reviewed the data of patients treated with NB-UVB between January 1998 and December 2013 at the Dermatology Unit of our University Hospital, to evaluate the cutaneous carcinogenic risk of NB-UVB. RESULTS: In all, 375 patients were included, each receiving a mean follow-up of 6.9 years. Vitiligo and psoriasis were the most common diseases. In total, 19 non-melanoma skin cancers (NMSCs) were diagnosed in eight patients, after a mean latency of 5.2 years after the first radiation. No malignant melanoma (MM) was observed. The incidence rates of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) were 620.2/100 ̇000 p/y and 116.3/100 ̇000 p/y. NMSCs were more frequent in patients affected by psoriasis (P = .0232), with older age at the first radiation (mean = 68.8 years, P = .0001). CONCLUSION: Despite the small number of patients and limited follow-up, our data suggest that NB-UVB may trigger cutaneous carcinogenesis, mainly in patients at risk for NMSCs, increasing their personal risk for single and multiple neoplasms, usually superficial BCCs. MM risk does not seem to be enhanced.