Risk of nonmelanoma skin cancers and cutaneous melanoma after psoralen and ultraviolet A therapy in patients with psoriasis: a nationwide Taiwanese cohort study.

BACKGROUND

Psoralen and ultraviolet A (PUVA) phototherapy is associated with an increased risk of nonmelanoma skin cancers and may be associated with cutaneous melanoma in White populations. However, data on the safety of PUVA phototherapy in Asian populations are scarce.

OBJECTIVES

To assess the risk of nonmelanoma skin cancer and cutaneous melanoma among patients with psoriasis receiving PUVA phototherapy.

METHODS

We conducted a nationwide Taiwanese cohort study spanning from 2001 to 2018 to assess the risk of PUVA phototherapy in relation to nonmelanoma skin cancer and cutaneous melanoma in patients with psoriasis.

RESULTS

Among 13 245 patients with psoriasis, PUVA phototherapy was associated with an increased risk of nonmelanoma skin cancer [adjusted hazard ratio (HR) 1.55, 95% confidence interval (CI) 1.03-2.32, P = 0.03]. The association remained consistent when considering the number of PUVA phototherapy sessions (adjusted HR 1.006, 95% CI 1.004-1.009, P < 0.001). Notably, neither PUVA phototherapy nor the number of PUVA phototherapy sessions revealed an increased risk of cutaneous melanoma (adjusted HR 0.90, 95% CI 0.24-3.42, P = 0.87; adjusted HR, 1.000, 95% CI 0.977-1.023, P = 0.99, respectively).

CONCLUSION

These findings suggest that PUVA phototherapy was associated with an increased risk of nonmelanoma skin cancer but not melanoma in Asian patients with psoriasis who have Fitzpatrick skin phototypes II-V. For patients with psoriasis who have received PUVA phototherapy, regular follow-up skin examinations are suggested.