UVB phototherapy not linked with skin cancer risk in vitiligo
No increase in skin cancer incidence was reported for patients with vitiligo undergoing prolonged narrowband ultraviolet B phototherapy, according to a study.
“Narrowband UVB phototherapy has been the mainstay in the treatment of vitiligo, but its long-term safety in terms of photocarcinogenesis has not been established,” Jung Min Bae, MD, PhD, of the department of dermatology at St. Vincent’s Hospital, College of Medicine at The Catholic University of Korea, Seoul, and colleagues wrote. They aimed to investigate risks for both skin cancer and precancerous lesions in patients with vitiligo as a function of the number of narrowband UVB phototherapy sessions they underwent.
The nationwide, population-based retrospective cohort analysis included 60,321 patients aged 20 years or older identified through the country’s national health insurance claims database. The study was conducted for the period between Jan. 1, 2007, and Dec. 31, 2017, and accounted for the number of phototherapy sessions undergone between 2008 and 2017.
Incidence of actinic keratosis, Bowen disease, nonmelanoma skin cancer or melanoma served as the primary outcome measure. The researchers grouped patients by frequency of phototherapy sessions, with 20,105 patients undergoing zero sessions, 20,106 undergoing one to 49 sessions, 9,702 undergoing 50 to 99 sessions, 6,226 undergoing 100 to 199 sessions, and 4,182 patients undergoing 200 sessions or more; 717 patients underwent at least 500 sessions.
Bowen disease risk failed to increase with each successive level of sessions, with the hazard ratio of 0.289 for 50 or fewer sessions (95% CI, 0.060-1.392) increasing only slightly for 50 to 99 sessions (HR = 0.603; 95% CI, 0.125-2.904), 100 to 199 sessions (HR = 1.273; 95% CI, 0.329-4.924) and 200 or more sessions (HR = 1.021; 95% CI, 0.212-4.919).
A similar pattern was observed for nonmelanoma skin cancer, with a hazard ratio less than 1 for patients undergoing fewer than 50 sessions (HR = 0.914; 95% CI, 0.533-1.567), 50 to 99 sessions (HR = 0.765; 95% CI, 0.372-1.576), 100 to 199 sessions (HR = 0.960; 95% CI, 0.453-2.034) and 200 or more sessions (HR = 0.905; 95% CI, 0.395-2.073).
Melanoma risk also carried a low hazard ratio for fewer than 50 sessions (HR = 0.660; 95% CI, 0.286-1.526) and remained manageable for 50 to 99 sessions (HR = 0.907; 95% CI, 0.348-2.362), 100 to 199 sessions (HR = 0.648; 95% CI, 0.186-2.255) and 200 or more sessions (HR = 0.539; 95% CI, 0.122-2.374).
Conversely, patients with vitiligo undergoing 200 or more phototherapy sessions were at an increased risk for actinic keratosis (HR = 2.269; 95% CI, 1.530-3.365).
Among the patients who underwent at least 500 phototherapy sessions, no increased risk was reported for nonmelanoma skin cancer (HR = 0.563; 95% CI, 0.076-4.142) or melanoma (HR = not applicable) compared with patients who did not undergo phototherapy. – by Rob Volansky
Disclosure: Bae reported receiving grants from the Ministry of Science, ICT & Future Planning outside the submitted work.