Narrow-band ultraviolet B (NBUVB) phototherapy has been the mainstay in treatment of vitiligo, but its long-term safety in terms of photocarcinogenesis has not been established. We performed a nationwide population-based retrospective cohort study to investigate the risks of actinic keratosis (AK), Bowen’s disease (BD), nonmelanoma skin cancers (NMSC), and melanoma, based on the number of NBUVB phototherapy sessions of patients with vitiligo.
We obtained cohort data from the Korean National Health Insurance Claims database for the period January 2007 to December 2017. We enrolled all patients with vitiligo aged ≥20 years and counted the numbers of phototherapy sessions each received between 2008 and 2017. We classified the patients into five groups according to the number of sessions and then performed frequency matching by age and sex: 0 sessions (n = 20,105), 1–49 (n = 20,106), 50–99 (n = 9,702), 100–199 (n = 6,226), and ≥200 (n = 4,182). We used a multivariate Cox’s proportional hazards model to explore the potential effect of NBUVB on the risk of skin cancer or development of premalignant lesions after adjusting for confounding factors.
We enrolled 60,321 patients with vitiligo. The risks of Bowen’s disease, nonmelanoma skin cancer, and melanoma did not increase after phototherapy; the risk of actinic keratosis increased significantly in those who had undergone ≥200 NBUVB sessions (hazard ratio, 2.280; 95% confidence interval 1.537–3.383). We then identified 717 patients with vitiligo who had undergone at least 500 sessions; their risks of nonmelanoma skin cancer and melanoma were no greater than those of the controls.
Our results imply that long-term NBUVB phototherapy does not increase the risk of skin cancer in patients with vitiligo and it can be considered a safe treatment.

Narrow-band ultraviolet B phototherapy does not increase the risk of skin cancer in patients with vitiligo: A nationwide population-based retrospective cohort study