WEDNESDAY, Dec. 13, 2023 -- Phototherapy is not associated with an increased risk for skin cancer, according to a study published online Dec. 7 in the Journal of the American Academy of Dermatology.

Elle Wang, from the University of British Columbia in Vancouver, Canada, and colleagues conducted a retrospective cohort study of patients treated at a teaching-hospital phototherapy center from 1977 to 2018. Age-standardized incidence rates (ASIR) of skin cancer were assessed for gender, skin phototype, diagnosis, ultraviolet modality, and anatomical site and were compared with provincial population incidence rates. Data were included for 3,506 patients treated with broadband-ultraviolet-B (UVB), narrowband-UVB, and/or combined UVAB, who were followed for a mean of 7.3 years.

Most patients had psoriasis or eczema (60.9 and 26.4 percent, respectively); patients received a median of 43 treatments. The researchers identified 170 skin cancers in 79 patients (17 melanoma, 33 squamous cell carcinoma [SCC], and 120 basal cell carcinoma [BCC]). The patient- and tumor-based ASIR of skin cancer was 149 and 264 per 100,000 person-years, respectively. No significant difference was seen between tumor-based ASIRs for melanoma, SCC, and BCC versus the general population, or in patients with psoriasis or eczema, or in those using immunosuppressants. There was no cumulative dose-response correlation noted between UVB and skin cancer.

"No increased risk of melanoma, SCC, and BCC compared to the general population was found in patients receiving phototherapy," the authors write. "This suggests ultraviolet phototherapy can be considered a relatively safe treatment option."