The World of UV Phototherapy

Dr. James Nordlund

Today I was reading the Winter Newsletter from Vitiligo Support International and one of the articles was edited and vetted by Dr. James Nordlund here in Cincinnati.

An often-expressed concern of both vitiligo patients and dermatologists is whether having vitiligo increases one’s risk for non-melanoma and/or melanoma skin cancer and if ultraviolet light therapy is a safe treatment. Though there are limited, but growing data, on this subject, key observations have been made which can help both the individual with vitiligo and dermatologist to better assess this risk. To effectively address the question, the information has been separated into these categories.

• Do vitiligo patients in general have an increased incidence of skin cancer?
• Do vitiligo patients have an increased risk of non melanoma skin cancer (NMSC) in their depigmented lesions?
• Do vitiligo patients have an increased risk of melanoma and/or NMSC in their “normal” skin?

Melanin is the substance that gives the skin its color, with darker skin having higher melanin levels. Melanin acts as a sunscreen and protects the skin from ultraviolet light which helps prevent sunburn damage that could result in DNA changes and, subsequently, melanoma. The assumption by many has been that that because the depigmented skin affected by vitiligo has no melanin, that the patient would be more susceptible to some types of skin cancer.

Because there are no melanocytes in depigmented skin, it would be biologically impossible to develop in depigmented skin a melanoma the most serious type of skin cancer. The other forms, the so called basal epithelioma, could develop but are easily treated and are not life threatening.

Unfortunately there are no great statistical studies on cancer in vitiligo. However most research and/or observations indicate that while non melanoma skin cancers do occur in vitiligo patients, they are very rare and melanomas in the normal skin occur at most, in no greater incidence than within the normal population.
An interesting observation on this subject was reported in the book Vitiligo: A Monograph on the Basic and Clinical Science, by Seung-Kyung Hann and James J. Nordlund. Dr. Nordlund observed that in East African countries near the equator, where few work indoors and sunscreen is unavailable, that people with vitiligo not only do not appear to get skin cancer, they exhibit little sun damage to their skin. Other studies also agree that vitiligo patients generally do not demonstrate sun-induced skin damage, despite the lack of protective melanin in the skin.

Ultraviolet light, both natural sunlight and artificial light in PUVA, Excimer laser and narrowband UVB, is an important therapeutic tool for vitiligo. To date, most studies agree that light used in accordance with a supervised treatment plan is a safe, effective method for treating vitiligo. More long term studies will be needed to further assess any skin cancer risk from these treatments.

VSI would like to thank Dr. James J. Nordlund, Professor of Dermatology, Group Health Associates, Cincinnati, OH and Wright State School of Medicine, for his significant contributions to, and medical review of this article.

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