311 Risk factors for the recurrence in patients with early endometrioid endometrial cancer achieving complete remission for fertility-sparing hormonal treatment

Introduction/Background This study aims to assess recurrence risk factors in patients with early-stage endometrioid endometrial cancer who have achieved complete remission (CR) through fertility-sparing hormonal treatment (FST). Methodology We retrospectively analyzed patients who received FST for presumed stage IA, grade 1 endometrioid endometrial cancer at two institutions. Medroxyprogesterone and levonorgestrel-releasing intrauterine devices were used concurrently for treatment. Cox regression analysis was used to identify the clinicopathological variables for recurrence-free survival (RFS) following CR. Results Among 180 patients with presumed stage IA, grade 1 endometrioid endometrial cancer who received FST, (n=144, 80.0%) had complete remission. The median time to achieve CR and the median duration of FST was 10 months (range 1–34) and 14 months (range 3–49), respectively. During the median follow-up period of 43.5 months (range 4–143), (n=85, 59.0%) patients had recurrence with median RFS of 13 months (range 1–123) after CR. On multivariable analysis, age (HR 1.062, 95% CI 1.016 to 1.110; P<0.05), and pregnancy (HR 0.185, 95% CI 0.085 to 0.405; P<0.05) were significantly associated with RFS. Conclusion Older age, non-pregnancy might be risk factors for early failure of first-line FST. Therefore, patients with these conditions should receive close and frequent follow-up, including imaging and histology examinations, to detect recurrence after complete remission. Disclosures COI: none.