Relationship between Menopausal Hormone Therapy and Oral Cancer: A Cohort Study Based on the Health Insurance Database in South Korea

The association between the development of oral cavity cancer and sex hormones is unclear and inconsistent. This study aimed to evaluate the relationship between menopausal hormone therapy (MHT) and oral cavity cancer in menopausal women in Korea. In this retrospective cohort study, data were provided by the Korean National Health Insurance Service regarding a screening examination conducted from 1 January 2002 to 31 December 2019. Postmenopausal patients aged ≥40 years were considered, including 333,072 women in the MHT group and 847,558 women in the non-MHT group. Participants were divided into MHT types (tibolone, combined estrogen plus progestin by manufacturer, estrogen, combined estrogen plus progestin by physician, and topical estrogen), and the risk factors for oral cavity cancer development were analyzed. There was no significant association between smoking, alcohol consumption, age at menarche, and age at menopause with oral cavity cancer in postmenopausal women. However, the oral estrogen (hazard ratio [HR]: 1.633; 95% confidence interval [CI]: 1.35–1.976) and tibolone groups (HR: 1.633; 95% CI: 1.35–1.976) were associated with an elevated risk of oral cavity cancer. The results of this study suggest that MHT increases the risk of oral cavity cancer in postmenopausal women.