Results from a large population-based, retrospective cohort study in Korea showed a substantial reduction in the overall risk of developing internal malignancies for individuals with vitiligo. 

Previous studies have shown that individuals with vitiligo have lower risks of skin cancers compared with non-vitiligo patients. In a British postal survey of 1,307 patients and their partners from 2013, patients with vitiligo had a threefold lower probability of developing skin cancers during their lifetimes than did those without vitiligo. In an Italian study from 2014, a cohort of 10,040 patients with vitiligo had a decreased risk of developing melanoma and nonmelanoma skin cancers compared to controls without vitiligo, but the exact mechanism wasn't clear. 

Jung Min Bae and colleagues conducted a population-based study to explore the risk of various internal malignancies in 101,078 patients with vitiligo using the 10-year Korean National Health Insurance claims database, which includes almost all medical information for 50 million individuals. The mean age was 48.7 ± 15.4 years, and 58.7% of the patients were women. 

After analysis was adjusted for age, sex, and comorbidities, the overall risk of internal malignancies was significantly lower in patients with vitiligo than in controls. With regard to specific organs, the colon and rectum, ovary, and lung — notably so in men — showed remarkably decreased risks of developing cancer in patients with vitiligo. The findings of this study are in sync with previous reports, and also support the hypothesis that autoimmunity has a protective effect against cancer cells of not only the skin but also internal organs in patients with vitiligo. 

Furthermore, the negative association between internal malignancies and vitiligo is theoretically plausible. Autoreactive cytotoxic T cells play a central role in the development of vitiligo by attacking melanocytes and may be involved in antitumor immune responses by killing tumor cells. Because most organs in this study showed a decreased trend in the incidence of cancer among patients with vitiligo, T-cell immunity is unlikely to be organ specific. Of the various cytokines associated with T-cell–mediated immune regulation, interferon gamma (IFN-g) is the key player in both antitumor immune responses against tumor cells and melanocyte destruction in vitiligo. 

Interestingly, the risk of thyroid cancer in this study was notably higher in patients with vitiligo compared with controls. This findings could be explained by the hypothesis that the chronic inflammatory microenvironment of the thyroid in patients with autoimmune thyroid disease may result in malignant transformation of thyroid tissue. 

The findings of this study could motivate physicians and researchers to investigate the systemic influence of the autoimmune nature of vitiligo.

Findings from this study were published online in the Journal of Clinical Oncology. J Clin Oncol. 2019 Apr 10;37(11):903-911. doi: 10.1200/JCO.18.01223. Epub 2019 Feb 20.

 

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