Long-term ultraviolet B phototherapy for dermatitis does not increase skin cancer risk

Key takeaways:

• Ultraviolet B phototherapy was not linked to an increased risk of skin cancer (adjusted HR = 0.91).
• The number of phototherapy sessions also did not increase the risk of skin cancer (aHR = 0.99).

The quality and quantity of ultraviolet B phototherapy sessions for the treatment of atopic dermatitis did not increase the risk of skin cancer development in patients, according to a study.

UVB phototherapy is a popular method of treatment for AD as it is affordable, can be used for patients with internal malignancies and avoids systemic toxicities or drug interactions. However, clinicians continue to worry that UVB phototherapy increases the risk of skin cancer, according to the study.

“Chronic ultraviolet exposure is the most important risk factor for skin cancer,” Mei-Ju Ko, MD, PhD, of the department of dermatology at Taipei City Hospital and the National Taiwan University Hospital and College of Medicine in Taipei City, Taiwan, and colleagues wrote. “Therefore, the long-term safety of UVB phototherapy is a major concern for clinicians and patients when choosing treatment.”

Comprised of 6,205 patients with AD, this nationwide population-based cohort study reported on the risk of UVB phototherapy skin cancer in these patients. The retrospective study included data from 2001 to 2018.

Results showed that UVB phototherapy did not increase the risk of skin cancer among patients with AD compared with healthy controls (adjusted HR = 0.91; 95% CI, 0.35-2.35). Similar findings were seen among nonmelanoma skin cancer (aHR = 0.8; 95% CI, 0.29-2.26) and cutaneous melanoma (aHR = 0.8; 95% CI, 0.08-7.64).

The number of UVB phototherapy sessions also did not increase the risk of skin cancer (aHR = 0.99; 95% CI, 0.96-1.02), nonmelanoma skin cancer (aHR = 0.99; 95% CI, 0.96-1.03) or cutaneous melanoma (aHR = 0.94; 95% CI, 0.77-1.15).

While strengths of this study included its large test population and long follow-up periods, the study was limited by its retrospective nature, according to the researchers.

However, Ko and colleagues concluded that these findings support previous evidence, stating, “Our results that UVB phototherapy does not increase the risk of skin cancer among AD patients are consistent with previously reported results from patients with psoriasis, vitiligo and chronic kidney disease.”