Patients who undergo narrowband UV-B phototherapy for vitiligo have no increased risk of developing skin cancer, but long-term therapy is associated with higher odds of actinic keratosis, researchers say.

In the Korean study of more than 60,000 patients with vitiligo in a national health insurance database — two-thirds of whom had the phototherapy — no link was found with melanoma or non-melanoma skin cancer over 10 years of follow-up.

This was true even for the 718 patients who had long-term phototherapy encompassing 500 sessions or more, the researchers wrote in JAMA Dermatology.

However, patients who had 200 sessions or more of phototherapy had double the risk of actinic keratosis compared with patients who were not treated with UV-B.