Adjuvant chemotherapy followed by adjuvant radiotherapy for treatment of high risk endometrial cancers: A retrospective review.

e17626 Background: Endometrial cancer is the most common gynecologic malignancy in North America (1-3). Patients who are considered to be high risk for recurrence are commonly treated with a combination of adjuvant chemotherapy and radiation. However, the optimal sequence of these therapies has not been defined. The purpose of this study is to review our progression-free survival (PFS) outcomes and recurrence rates and compare to established outcomes in the literature. Methods: A retrospective chart review was performed on all patients diagnosed with endometrial cancer who received adjuvant chemotherapy and radiation between Jan. 1, 2005 to Dec. 31, 2017 at The Ottawa Hospital. Main inclusion criteria for the study were stage III endometrial cancers of any histology, stage I-II endometrial cancers with serous or clear cell histology and stage IV endometrioid adenocarcinomas of the endometrium. The primary outcome of interest is the overall progression-free survival (PFS), defined as the time from surgery to disease recurrence or death by any cause. Results: A total of 140 patients were included in the study. Of these, 52 (37.1%) had endometrioid histology, 75 (53.6%) had serous, and 11 (7.9%) had clear cell histology. Of the total sample, 41 (29.3%) were stage 1 at diagnosis, 24 (17.1%) were stage 2, 68 (48.6%) were stage 3 and 7 (5.0%) were stage 4. The median start time to chemotherapy was 49 days after initial surgery. 130 (92.9%) completed a total of 6 cycles of chemotherapy (majority treated with carboplatin and paclitaxel). 92% of the patients completed radiation following chemotherapy; majority received external beam radiation +/- a brachytherapy boost. Radiation was started withing 4-6 weeks of completing chemotherapy. 42 (30.0%) patients were diagnosed with a recurrence during the time of follow-up and 7 were diagnosed with progressive disease on treatment. Of the recurrences, 2 (4.8%) were local, 5 (11.9%) were locoregional, 8 (19.0%) were isolated para-aortic, and 27 (64.3%) were distant. The median follow-up time for our sample was 63.9 months. The median PFS and overall survival for our sample was not reached. The estimated mean 5 year PFS was 0.69 and OS was 0.66. Conclusions: Although radiation prevents locoregional recurrences, chemotherapy improves survival outcomes in locally advanced and aggressive histology endometrial cancer. Previous reported outcomes have been based on giving adjuvant radiation first, followed by chemotherapy (4,5). Our results demonstrate that giving adjuvant chemotherapy first and then delivering radiation after may be the optimal approach since it leads to survival outcomes that compare favourably with the published literature and very few locoregional relapses.