Abstract
OBJECTIVE: To evaluate the disease course of patients with low grade endometrial stromal sarcoma (LG-ESS) and compare oncologic outcomes associated with hormonal therapy in primary and recurrent disease. METHODS: This is a retrospective study of patients with LG-ESS who underwent active treatment between January 2000 and July 2023. Recurrence-free survival (RFS) and overall survival (OS) were estimated using the Kaplan-Meier product-limit estimator and modeled via Cox proportional hazards regression. RESULTS: A total of 221 patients were included; 58 % of patients (91/157) were stage I, 12 % (19/157) stage II, 13 % (20/157) stage III, and 17 % (27/157) stage IV. Surgery was the primary treatment for 98 % (213/218). Only 79 patients received hormonal adjuvant therapy, 58 % (46/79) Megace, 24 % (19/79) Letrozole, and 18 % (14/79) received other hormonal therapy. There was no significant difference in RFS (p = 0.159) and OS (p = 0.167) between patients receiving Megace versus Letrozole as adjuvant therapy. At first recurrence, patients given Megace had a similar RFS to those on Letrozole (p = 0.302), but a better OS (27 vs 10 months, p = 0.018). Negative status of estrogen, smooth muscle actin, and desmin were associated with lower RFS (p = 0.039, p = 0.002, and p = 0.015, respectively) and OS (p = 0.008, p = 0.012, and p = 0.013, respectively). Lymphovascular invasion was associated with lower RFS (p = 0.033), and negative status of progesterone was associated with lower OS (p = 0.003). CONCLUSION: There was no difference in oncologic outcomes between Megace and Letrozole in patients who received adjuvant therapy for LG-ESS. Megace may have potential survival advantage in recurrent disease. Further study is warranted to determine the most effective agents and their sequence in the treatment of LG-ESS.