People with vitiligo, one of the most common skin diseases, are three times less likely to develop skin cancer, new research due to be published in the British Journal of Dermatology will reveal.
Vitiligo is a condition in which areas of skin lose their normal pigment and so become white. It is common, affecting about one in every hundred people in the world, and as it can be very visible, it is often a psychological burden to patients.
However a study carried out by researchers in The Netherlands has discovered that vitiligo patients have a threefold lower chance of developing both melanoma, the least common but deadliest type of skin cancer, and non-melanoma skin cancers, which are less dangerous but more common.
The scientists compared skin cancer rates in 1307 vitiligo patients, compared to 788 control subjects without vitiligo. They also examined other factors that might influence skin cancer development, such as sun exposure, number of sunburns in childhood, sun protective measures, outdoor work or hobbies and the individual’s number of moles, and these variables were factored into the results.
Of the 1307 patients with vitiligo who answered the survey, seven (0.54%) had been diagnosed with melanoma during their lifetime. All melanomas had occurred in areas of skin not affected by the vitiligo. Of the 788 non-vitiligo controls, 12 individuals (1.53%) had been diagnosed with 14 melanomas. When the results were adjusted for other risk factors, vitiligo remained associated with a threefold decreased likelihood of developing this skin cancer
The results were similar for non-melanoma skin cancers (basal cell carcinoma and squamous cell carcinoma). 30 of the vitiligo patients had been diagnosed with a total of 37 basal cell carcinomas (BCCs) during their lifetimes. In addition, five patients with vitiligo had each been diagnosed with one squamous cell carcinoma (SCC), and one patient had experienced one BCC and one SCC (a total of 44 non-melanoma skin cancers in 36 patients). In the control group, 47 of 788 non-vitiligo volunteers had been diagnosed with a total of 61 BCCs, and four patients had suffered an SCC (a total of 65 non-melanoma skin cancers in 51 patients). When adjusted for all risk factors that were significantly associated with non-melanoma skin cancer development in the analysis, patients with vitiligo had a threefold decreased probability of non-melanoma skin cancer.
Dr Hansje-Eva Teulings of the University of Amsterdam and one of the study’s authors said: “We observed a significant threefold lower odds for melanoma during lifetime in vitiligo patients. The anti-melanocyte immune response in vitiligo, in which melanocytes are destroyed in the skin, may be responsible for the observed decrease in melanoma lifetime prevalence.
“We also found that patients with vitiligo have a threefold decreased probability of developing non-melanoma skin cancer during their lifetime. This finding seems to be counterintuitive, as the lack of protective pigmentation is supposed to increase the risk of these cancers. The lower probability may relate to the observed decreased photodamage and increased levels of wild-type p53 expression in keratinocytes (skin cells) in patients with vitiligo. This is a tumour suppressor which may protect against UV damage and the development of keratinocyte cancer.”
Nina Goad of the British Association of Dermatologists said: “A very interesting aspect of this study is that no increased skin cancer prevalence was seen in phototherapy-treated patients compared with patients who had never undergone phototherapy. This differs from patients with another common skin disease, psoriasis, where long-term phototherapy treatment has been linked to an increases risk of some skin cancers. As phototherapy is one of the recommended treatments for vitiligo, this may prove a very positive finding.
“Similarly, vitiligo patients may worry that their paler patches of skin are more likely to develop skin cancer, as it is generally known that people with fairer skin types are more at risk of the disease. However this is not the case for skin that is affected by vitiligo.
“Vitiligo can have a strong psychological and emotional impact as it can be very visible, especially in darker skin types, so any research that eases the burden on these patients is most welcome.”
The pigment that gives skin its normal colour is melanin, which is made by cells called melanocytes. In patches of vitiligo the melanocytes are absent, and the reason for this is not fully understood. However, vitiligo is considered to be an autoimmune condition in which the body’s own immune system rejects some of its own tissues (melanocytes in the case of vitiligo). It affects men and women of all ethnicities equally, but is most obvious in people with dark skin.