Effects of hormone therapy on recurrence in endometrial cancer survivors: A nationwide study using the Korean Health Insurance review and assessment service database

Objective: The aim of this study was to verify the effects of hormone therapy (HT) on recurrence in endometrial cancer (EC) survivors using the Korean Health Insurance Review and Assessment Service (HIRA) database. Methods: Using the HIRA claims database, we identified all Korean women who were newly diagnosed with EC and underwent surgical staging between 2010 and 2013. Patient characteristics such as age, HT exposure, lymphadenectomy, and adjuvant therapy were evaluated. Cox proportional hazards models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the recurrence of EC. Results: The mean follow-up time of all 5,667 eligible patients was 47.5 months. Of these, 847 (14.9%) received HT. Recurrence was seen in 446 (7.8%) patients. Univariate analysis revealed an increased recurrence rate in patients older than 50 years (HR=2.05; 95% CI=1.62–2.63), patients with high-risk EC (HR=24.51; 95% CI=18.63–32.35), and patients who underwent lymphadenectomy (HR=1.52; 95% CI=1.21–2.03), and a reduced recurrence rate in patients who received HT (HR=0.62; 95% CI=0.46–0.83). Multivariate analysis confirmed the significant increase in recurrence in patients older than 50 years (HR=1.47; 95% CI=1.14–1.89) and in patients with high-risk EC (HR=23.90; 95% CI=18.12–31.51). HT did not increase the recurrence rate of EC (HR=0.81; 95% CI=0.31–2.10). Conclusion: This study demonstrates that HT does not increase disease recurrence in EC survivors, despite lack of data that could affect the outcome.