Study reveals Hashimoto's thyroiditis does not increase melanoma risk

The findings published in the Archives of Dermatological Research suggest that the local proinflammatory environment present in Hashimoto does not significantly contribute to the risk of melanoma.

Hashimoto's is an autoimmune disorder. Normally, the autoimmune system protects the body by attacking viruses and bacteria. But with the disease, the immune system attacks the thyroid gland by mistake. The thyroid fails to produce sufficient thyroid hormone, resulting in body dysfunction.

An inflammatory microenvironment has been suggested to raise the risk of malignant melanoma, indicating that melanoma may be related to an inflammatory state. Hashimoto’s thyroiditis is one of the most common autoimmune diseases, yet no study has been conducted on its relationship with melanoma.

B. G. Gorman, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA, and colleagues aimed to determine whether Hashimoto’s increases the risk of developing melanoma in a retrospective study.

For this purpose, the researchers identified a retrospective, validated cohort of patients with Hashimoto’s diagnosis between 2005 and 2020 using the Olmsted County database. Patients were sex and age-matched to controls without a Hashimoto diagnosis. The study's primary outcomes were the melanoma development and the time to first diagnosis of melanoma.

The study led to the following findings:

• 4805 patients were included in the study, with 36% having a diagnosis of Hashimoto’s.
• Hashimoto’s patients had no significant difference in risk of melanoma (relative risk 0.96) or nonmelanoma skin cancer (relative risk 0.95) compared with matched controls, suggesting that, despite its potential pro-inflammatory effects, Hashimoto's thyroiditis does not appear to contribute to the risk of melanoma significantly.

"The study findings suggest that Hashimoto's thyroiditis does not increase the risk of melanoma and NMSC," the researchers wrote.

"There may be a need for larger studies to characterize the relationship between these diseases further," they concluded.

Reference:

Gorman, B.G., Campbell, E., Mullen, B.L. et al. Association between Hashimoto’s thyroiditis and melanoma: a retrospective matched cohort study. Arch Dermatol Res 315, 2721–2724 (2023). https://doi.org/10.1007/s00403-023-02669-4