Sun, Charlotte C.

5595 Background: Endometrial cancer is the most common cancer of the female genital tract. It affected 41,200 women in the year 2006 and caused 7,350 deaths. Therapy options for recurrent/advanced endometrial cancer are limited. Treatment with radiation and chemotherapy has shown only limited success. Methods: In a phase II IRB approved trial, Mifepristone was given to patients with progesterone receptor positive advanced or recurrent endometrioid adenocarcinoma or low-grade endometrial stromal sarcoma at a dose of 200mg/day orally. Patients were evaluated every 4 weeks to assess treatment-related toxicities and response. Imaging was obtained initially at 8 weeks then every 12 weeks for evaluation of response. Common Terminology Criteria for Adverse Events (CTCAE), version 3.0 was used to assess toxicity. Results: Twelve of 13 enrolled patients were evaluable for response in the first phase of accrual. Stable disease was noted in 3/12 (16, 20, and 44+ weeks). Two were endometrioid endometrial cancer and one with LGESS. No complete responses were seen, one patient remains in treatment. The most frequently reported grade 1–2 tumor related toxicities were anorexia, mood alterations, and fatigue (55%). Twenty-seven percent had asymptomatic elevations of ACTH. The most common Grade 3 toxicities were fatigue and dyspnea (27% and 18%). Only one patient experienced a Grade 4 dyspnea. No serious treatment-related adverse events occurred. Conclusions: Single agent mifepristone in patients with recurrent endometrioid adenocarcinoma or low-grade endometrial stromal sarcoma showed no complete responses. Stable disease was reported 25%, one patient remains stable at 44 weeks. Recent reports suggests that mifepristone may also work via non hormonal targets while single agent mifepristone has minimal activity in this setting. Further evaluation in combination therapy in endometrial cancer should be considered. No significant financial relationships to disclose.

10 Background: Our objective was to evaluate the cost-utility of 3 lymphadenectomy (LND) strategies in the treatment of low-risk endometrial cancer (EC). Methods: A decision analysis model compared 3 LND strategies in women undergoing minimally invasive surgery (MIS) for EC: 1) routine LND in all pts; 2) selective LND based on intraoperative frozen section, in which 60% of pts undergo LND; and 3) sentinel lymph node mapping (SLN) based on a published algorithm, in which 15% of pts map unilaterally (requiring a contralateral LND) and 5% don’t map (requiring bilateral LND). Costs and outcomes were obtained from published literature and Medicare reimbursement rates. Costs categories consisted of hospital, physician, operating room, pathology, and lymphedema treatment. Effectiveness was defined as 3-year disease-specific survival adjusted for the impact of lymphedema (utility = 0.8) on quality of life. Incremental cost-effectiveness ratios (ICERs) per quality-adjusted life years (QALYs) gained were calculated. QALYs and costs were discounted at an annual 3% rate. Results: For the estimated 40,000 women undergoing surgery for low-risk EC each year in the US, the annual cost of routine LND, selective LND, and SLN is $722 million, $681 million, and $656 million respectively. In the base case scenario, routine LND had a cost of $18,041 and an effectiveness of 2.79 QALYs. Selective LND had a cost of $17,036 and an effectiveness of 2.81 QALYs, while SLN had a cost of $16,401 and an effectiveness of 2.87 QALYs. With a difference of $1,005 and 0.02 QALYs, selective LND was both less costly and more effective than routine LND, dominating it. However, with the lowest cost and highest effectiveness, SLN dominated the other modalities and was the most cost-effective strategy. No ICER could be determined. These findings were robust to multiple one- and two-way sensitivity analyses varying the rates of lymphedema and LND, surgical approach (open or MIS), lymphedema utility, and costs. Conclusions: Compared to routine and selective LND, SLN had the lowest cost and highest quality-adjusted survival, making it the most cost-effective strategy in the management of low-risk EC.