174 - Poster Session Oncologic outcome of stage IIA1 cervical cancer: Is surgical treatment justified? Y. Yagur a , O. Weitzner a , R. Eitan b , A. Fishman a , L. Helpman a , c . a Meir Medical Center, Kfar Saba, Israel, b Rabin Medical Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel, c Juravinski Hospital and Cancer Centre, Hamilton Health Sciences, Hamilton, ON, Canada Objective: Data on the outcome of stage IIA cervical cancer are limited, as these tumors account for a small percentage of early tumors. National Comprehensive Cancer Network guidelines suggest consideration of surgical management for small tumors with vaginal involvement. Since stratification of the risk of postoperative radiation is essential to select patients for surgical management, our objective in this study was to assess the risk of adjuvant radiotherapy in stage IIA cervical cancer and to investigate its associated features. Methods: This was a retrospective cohort study comparing surgically treated cervical cancer patients with stage IB1 and stage IIA disease. Women treated between 2000 and 2015 in 10 Israeli medical centers were included in the study. Data were abstracted from the medical records. Patient and disease features were compared between stages. The relative risk (Fisher exact test) of receiving postoperative radiation was calculated and compared for each risk factor. A general linear model (GLM) was used for multivariate analysis, after confirmation of no collinearity among the risk factors using the variation inflation factor (VI F = 1.04–1.48). Results: A total of 300 patients were included, of whom 28 patients had stage IIA disease. Patient and disease characteristics were comparable for stage IB1 and stage IIA1 disease, although the rate of close or involved surgical margins was higher for patients with vaginal involvement (23% vs 9.3%, P = 0.02). Patients were more likely to receive radiation after surgery for stage IIA disease (75% vs 52%, RR = 1.437, 95% CI 1.13–1.83, P = 0.027). The performance of a preoperative MRI was associated with a decreased risk for adjuvant radiotherapy (RR = 1.90, 0.96–3.74, P = 0.03). Stage was not an independent predictor of radiation on multivariate general linear modeling, whereas tumor diameter, LVI, and lymph node metastases were. See Table 1. Conclusion: Cervical cancer patients with vaginal involvement are highly likely (75%) to require postoperative radiation, although this may be mediated by other pathological risk factors. These patients need to be considered for primary chemoradiation, and careful selection should be employed before surgical management may be offered. doi:10.1016/j.ygyno.2018.04.184 175 - Poster Session Tozzi classification of diaphragmatic surgery in patients with stage IIIC-IV ovarian cancer based on surgical complexity and morbidity R. Tozzi a , H. Soleymani Majd b , F. Ferrari c , R. Garruto Campanile b . a Oxford University Hospital, Oxford, United Kingdom, b Oxford University Hospitals NHS Trust, Oxford, United Kingdom, c University of Brescia, Italy, Brescia, Italy Objective: To introduce a systematic classification of diaphragmatic surgery in patients with ovarian cancer based on the disease spread, the complexity of the procedure, and the complication rate. Method: For all consecutive patients who underwent diaphrag- matic surgery during visceral-peritoneal debulking (VPD) in the period 2009–2017, we extracted the following information: initial surgical finding, extent of liver mobilization, type of procedure performed, and intra- and postoperative specific complication rate. Combining these features, we aimed to define the surgical procedures necessary to tackle different presentation of diaphragmatic disease. Results: A total of 170 patients were included in this study; 110 (64.7%) had a peritonectomy, while 60 (35.3%) had a full thickness resection with pleurectomy. We identified 3 types of procedures in relation to increasing tumor spread, surgical complexity, and morbidity rate. Type 1 treated 28 out of 170 patients (16.5%) who only had anterior diaphragm disease, needed no liver mobilization, included peritonectomy, and had no morbidity recorded. Type 2 pertained to 105 out of 170 patients (61.7%) who had anterior and posterior disease, needed partial and sometimes full liver mobili- zation, had a mix of peritonectomy and full thickness resection, and experienced 10% specific morbidity. Type 3 included 37 out of 170 patients (21.7%) who needed full mobilization of the liver, always had full thickness resection, and suffered 30% specific morbidity. Conclusion: Diaphragmatic surgery can be effectively classified in 3 types based on initial findings, surgical complexity, and morbidity rate. A widespread adoption of this classification can facilitate standardization of the surgery and comparison of data and accurately define the level of expertise required. The latter can in turn assist patient referral to centers where appropriate expertise is available. Finally, this classification can be a benchmark to establish the training required to treat diaphragmatic disease. doi:10.1016/j.ygyno.2018.04.185 176 - Poster Session Outcomes of secondary cytoreductive surgery for patients with recurrent epithelial ovarian cancer A.A. Gockley a , b , A. Cronin c , M.A. Bookman d , R.A. Burger e , M. Cristea f , J.J. Griggs g , G.M. Mantia-Smaldone h , L.A. Meyer i , D.M. O'Malley j , A.A. Wright a . a Harvard Medical School, Boston, MA, USA, b Brigham and Womens Hospital, Boston, MA, USA, c Dana-Farber Cancer Institute, Boston, MA, USA, d US Oncology Research and Arizona Oncology, Tucson, AZ, USA, e University of Pennsylvania, Philadelphia, PA, USA, f City of Hope, Duarte, CA, USA, g University of Michigan Health Systems, Ann Arbor, MI, USA, h Fox Chase Cancer Center, Philadelphia, PA, USA, i The University of Texas MD Anderson Cancer Center, Houston, TX, USA, j The Ohio State University, James Cancer Hospital, Columbus, OH, USA Objective: The primary objectives of this study were to describe the clinical characteristics of patients with platinum-sensitive recurrent epithelial ovarian cancer (ROC) who underwent secondary cyto- reductive surgery (SCS) versus second-line chemotherapy (CT) and to identify factors associated with overall survival of patients treated with SCS versus CT. Table 1 Relative risk of receiving postoperative radiation. Parameter Relative Risk PValue Stage IIA (ref, IB1) 1.44 (1.13–1.83) 0.03 MRI omitted (ref, performed) 1.90 (0.96–3.74) 0.03 PET omitted (ref, performed) 1.058 (0.86–1.3) 0.64 Lymph node involvement (ref, none) 2.28 (1.96–2.66) b0.001 Tumor diameter (ref, b20 mm) 20–b40 1.36 (0.99–1.86) 0.06 ≥40 1.96 (1.44–2.68) b0.001 Depth of invasion (ref, b5 mm) 5–9 0.78 (0.48–1.27) 0.33 10–19 1.28 (0.9–1.83) 0.18 ≥20 1.95 (1.39–2.76) b0.001 LVSI (ref, none) 2.28 (1.87–2.77) b0.001 Parametrial involvement (ref, none) 1.81 (1.48–2.20) b0.001 Surgical margins close or involved 1.43 (1.12–1.83) 0.03 Abstracts / Gynecologic Oncology 149 (2018) 2–247 81