SUMMARY: Vitiligo is a common acquired skin disorder affecting 1% of the population worldwide. Vitiligo is generally considered to be an autoimmune disorder and is characterized by destruction of melanocytes resulting in patchy loss of skin pigmentation. CD8 positive T cells have been implicated in the progression of Vitiligo. Approximately 15-25% of individuals with Vitiligo are also affected by at least one other autoimmune disorder, such as autoimmune Thyroid disease, Rheumatoid arthritis, type 1 Diabetes, Psoriasis, Pernicious anemia, Addison disease, or Systemic Lupus Erythematosus.
There is epidemiologic evidence demonstrating reduced risks of both Melanoma and non-Melanoma skin cancers (NMSCs) in patients with Vitiligo, suggesting that Vitiligo-associated autoimmunity exerts immune surveillance on skin cells other than melanocytes. Further, it has been shown that the occurrence of de novo Vitiligo following treatment with Immune Checkpoint Inhibitors may be a surrogate marker for improved survival in patients with advanced Melanoma. This suggests that increased T-cell activity following blockade of immune checkpoints, targets cancer cells as well as melanocytes in the skin.
The benefit of increased T-cell activity on cancers of internal organs in patients with Vitiligo, however has been unclear. In this publication, the authors evaluated whether autoreactive T-cell responses to melanocytes in patients with Vitiligo would affect tumor immunosurveillance in different internal organs.
We conducted a nationwide population-based cohort study to explore the risk of internal malignancies in patients with Vitiligo using the 10-year Korean National Health Insurance (NHI) claims database from 2007-2016. This study included 101,078 patients with Vitiligo and 202,156 controls without Vitiligo. Patients were 20 years or older with Vitiligo and had at least two contacts with a physician. The authors examined the overall risk for the development of internal malignancies and organ-specific cancer risks in each group.
It was noted that after the analysis was adjusted for age, sex, and comorbidities, the overall risk of internal malignancies was significantly lower in patients with Vitiligo than in controls (HR=0.86; P<0.001). This risk reduction was more so in men than in women and younger patients 20-30 yrs old with Vitiligo, had notably reduced risk than patients 40 yrs or older. With regards to organ-specific malignancies, patients with Vitiligo had a remarkably decreased risk of cancer in the Colon and Rectum (HR=0.62; P<0.001), Ovary (HR=0.62; P<0.001), and Lung (HR=0.75; P<0.001).
It was concluded that Vitiligo was associated with a reduced risk of internal malignancies overall. The authors from the findings of this study postulated that autoimmune diseases, including Vitiligo, may provide immune surveillance for the development of cancer beyond the targeted organ. Markedly Reduced Risk of Internal Malignancies in Patients With Vitiligo: A Nationwide Population-Based Cohort Study. Bae JM, Chung KY, Yun SJ, et al. J Clin Oncol 2019;37:903-911
