Ultraviolet B phototherapy does not increase the risk of skin cancer among patients with atopic dermatitis: A population-based retrospective cohort study.

BACKGROUND: UV-B phototherapy is a common treatment modality for patients with atopic dermatitis (AD), but its long-term safety in terms of cutaneous carcinogenic risk has not been studied. OBJECTIVE: To investigate the risk of skin cancer among patients with AD receiving UV-B phototherapy. METHODS: We conducted a nationwide population-based cohort study from 2001 to 2018 to estimate the risk of UV-B phototherapy for skin cancer, nonmelanoma skin cancer, and cutaneous melanoma in patients with AD. RESULTS: Among 6205 patients with AD, the risks of skin cancer (adjusted hazard ratio [HR], 0.91; 95% CI, 0.35-2.35), nonmelanoma skin cancer (adjusted HR, 0.80; 95% CI, 0.29-2.26), and cutaneous melanoma (adjusted HR, 0.80; 95% CI, 0.08-7.64) did not increase among patients with AD treated with UV-B phototherapy, compared with those who did not receive UV-B phototherapy. Additionally, the number of UV-B phototherapy sessions was not associated with an increased risk of skin cancer (adjusted HR, 0.99; 95% CI, 0.96-1.02), nonmelanoma skin cancer (adjusted HR, 0.99; 95% CI, 0.96-1.03), or cutaneous melanoma (adjusted HR, 0.94; 95% CI, 0.77-1.15). LIMITATIONS: Retrospective study. CONCLUSION: Neither UV-B phototherapy nor the number of UV-B phototherapy sessions was associated with an increased risk of skin cancers among patients with AD.