From the 2009 ASCO Annual Meeting
Background: Endometrial stromal sarcomas (ESS) traditionally have been classified as low grade or high grade based on mitotic activity and histologic appearance. High-grade tumors are currently referred to as undifferentiated uterine sarcomas and are not included in this series. ESS are known to have high expression of estrogen and progesterone receptors. This is a retrospective study of patients with metastatic ESS treated with hormonal therapy. Methods: Following approval by the institutional review board all patients diagnosed with ESS from 1987-2007 were identified. Clinical and demographic information were abstracted from the charts and all histologic materials were re-reviewed. Estrogen and progesterone receptor testing was performed utilizing mouse monoclonal antibodies and the Cell Analysis Systems 200 Image analyzer. Survival was calculated using the Kaplan-Meier method and comparisons utilized the log rank test. Results: Thirteen patients with ESS were identified during this period. Seven had disease confined to the uterus. Six had extrauterine disease; 5 patients presented with metastases and 1 patient presented with a pelvic recurrence 20 years following a hysterectomy. All underwent surgical resection except for 1 patient that declined surgery. All 6 patients with metastases had tumors that tested positive for estrogen and progesterone receptors; all were treated with megestrol acetate initially for a period of 1-4 years. Two patients were then changed to maintenance with medroxyprogesterone acetate. Three patients with persistent disease were changed to aromatase inhibitors; 1 to letrozole and 2 to anastrazole. One of these patients has had a complete response and 2 have had stable disease. One patient has been lost to follow-up. Follow-up for the 6 patients was 2-22 years; no known patients died of their disease. Actuarial 2- and 5-year survivals were 80% and 65%, respectively. There was no significant difference in survival between patients with metastases and without metastases. Conclusions: ESS tumors are relatively uncommon and there is an absence of studies to guide treatment of patients with metastases. This experience indicates that these tumors respond well to hormonal manipulation. Treatment with progestins or aromatase inhibitors may result in remission or stable disease.