Markedly Reduced Risk of Internal Malignancies in Patients With Vitiligo: A Nationwide Population-Based Cohort Study

PURPOSE Recent studies indicated that the autoimmunity of vitiligo exerts effects on cells other than melanocytes, which confer reduced risks of both melanoma and nonmelanoma skin cancers in patients with vitiligo. However, the risk of internal malignancy in patients with vitiligo has not been elucidated. PATIENTS AND METHODS We conducted a population-based retrospective cohort study using data from the Korean National Health Insurance claims database obtained from January 2007 to December 2016. All patients age 20 years or older with vitiligo who had at least two contacts with a physician from 2009 to 2016, during which a principal diagnosis was made, were identified (vitiligo group). Controls were randomly selected (two per patient with vitiligo) after frequency matching with the vitiligo group for age and sex during the same period (control group). RESULTS A total of 101,078 patients with vitiligo and 202,156 controls without vitiligo were included. The incidence rates of internal malignancies were 612.9 and 708.9 per 100,000 person-years in the vitiligo and control groups, respectively. Patients with vitiligo showed a significantly reduced risk of overall internal malignancies (hazard ratio [HR], 0.86; 95% CI, 0.82 to 0.89; P < .001) compared with controls without vitiligo after adjustments for age, sex, and comorbidities. With regard to organ-specific malignancies, patients with vitiligo showed a remarkably decreased risk of cancer in the colon and rectum (HR, 0.62; 95% CI, 0.55 to 0.69; P < .001), ovary (HR, 0.62; 95% CI, 0.46 to 0.83; P < .001), and lung (HR, 0.75; 95% CI, 0.65 to 0.86; P < .001). CONCLUSION Vitiligo was associated with a reduced risk of overall internal malignancies. These findings suggest that autoimmune diseases, including vitiligo, may provide immune surveillance for the development of cancer beyond the targeted organ. (C) 2019 by American Society of Clinical Oncology