930P - A retrospective single institution study evaluating clinical outcome and prognostic markers for endometrial and ovarian carcinosarcomas (CS) U.Asghar1, G.Imseeh1, AA.Kirkwood2, M.Widschwendter1, A.Olaitan1, N.Macdonald1, T.Mould1, M.McCormack1, A.Mitra1, J.Ledermann1,2, R.Arora1 and R.Kristeleit1,2. 1Unversity College Hospital, 235 Euston Road, London; 2 Cancer Research UK and UCL Cancer Trials Centre, 90 Tottenham Court Road, London. Background  Table 2: Baseline patient and tumour characteristics Figure 1: OS of endometrial and ovarian CS Figure 2: OS according to FIGO staging CS are rare, heterogeneous tumours predominantly arising from the uterus, and less frequently the ovaries. They are aggressive gynaecological cancers with a poor prognosis. Histologically both carcinomatous (epithelial) and sarcomatous (mesenchymal) elements co-exist. Uterine CS can be further defined based upon their sarcomatous component as either homologous type (endometrial or smooth muscle) or heterologous type (skeletal, muscle or bone)1. Aims To assess whether (1) the clinical outcome for ovarian vs. endometrial CS were comparable, (2) the epithelial histological subtype or the presence of heterologous elements in the mesenchymal component impacted overall survival (OS), (3) If a personal or family history (FHx) of cancer was associated with OS. Figure 3: OS according to heterologous component Figure 4: OS according non adenocarcinoma vs. adenocarcinoma Methods  Women treated at University College London Hospital (UCLH) Gynae-oncology Unit between April 2002 – 2013 were identified retrospectively using electronic records. The data collected included demographic characteristics, FHx, risk factors, FIGO staging, the management details and the pathological reports. Methods  82 patients (72 endometrial and 10 ovarian), diagnosed between 1st April 2002 and 17th April 2013 with a median age of 67 (40 – 93) years were identified. 22% had a positive cancer history and 3.6% previously received abdominal/pelvic radiotherapy (RT). The median OS was 26.7 months. All ovarian CS patients had surgical resection (SR), 90% completed 6 cycles of postoperative carboplatin/paclitaxel chemotherapy (CT) with 20% complete responses (CR) and 40% partial responses (PR). 61% of endometrial CS patients were treated with SR, CT +/- RT. The response rates after CT were 57% CR and 9% PR.   Table 3: Survival according to baseline characteristics Conclusions  The clinical outcome for ovarian (12%) vs. endometrial CS were comparable in regards to OS (figure 1). The FIGO stage was the only statistically significant prognostic factor for OS (figure 2). Neither personal history nor FHx of cancer were associated with OS (table 3). Interestingly, CS tumours with predominately poorly differentiated adenocarcinoma and/or absence of heterologous components had trends for worse survival, although statistically not significant (figures 3 and 4). This warrants further clinical evaluation and longer follow-up is needed to see if this trend remains. Table 1: Response rates to SR, CT +/- RT References 1. Rani Kanthan and Jenna-Lynn Senger. Uterine Carcinosarcomas (Malignant Mixed Müllerian Tumours): A Review with Special Emphasis on the Controversies in Management. Obstet Gynecol Int 2011; 2011: 470795.