RT Journal Article SR Electronic T1 EP1044 Preoperative computed tomography predict unresectability in primary cytoreductive surgery for advanced ovarian cancer JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A552 OP A553 DO 10.1136/ijgc-2019-ESGO.1087 VO 29 IS Suppl 4 A1 Zuo, J A1 Wu, L A1 Dai, J YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_4/A552.3.abstract AB Introduction/Background The volume of residual tumor is a independent prognosis factor for advanced ovarian cancer. computed tomography (CT) is a widely adopted non-invasive methods for access the tumor dissemination and respectability. With neoadjuvant chemotherapy gain popularity, the extent of multivisceral techniques require further evaluation by CT imagings. The objective of this study was to estimate the value of preoperative CT in predicting suboptimal cytoreductive surgery in advanced ovarian serous cancer.Methodology From January 2011 to December 2018, patients histologic diagnosed of stage IIIC-IV ovarian cancer enrolled in this retrospective study, underwent primary cytoreductive surgery in national cancer center china, Abdomen/pelvis CT scans were obtained 2 weeks before primary surgery, an experienced radiologist was trained by 50 cases and then proposed 13 radiologic criteria measured by 2–4 quantitative scores, all CT imagings were retrospectively analyzed by 13 radiologic criteria which were blinded to the surgical exploration results.Results A total of 302 patients were enrolled in this study; optimal cytoreduction was achieved in 72.8%. The overall sensitivity of CT in predicting suboptimal primary Cytoreduction was 91%, the specificity was 84% and the positive predictive value was 69% and the negative predictive value was 96%. all patients were set up on condition that no more than two muiltivisceral procedures were applied. On multivariate analysis, five radiologic criteria were significantly associated with suboptimal cytoreductive surgery: perisplenic and diaphragm lesion>1 cm (P<0.0001); Liver metastasis or hilar lesion>1 cm (P<0.0001); suprarenal retroperitoneal lymph nodes >1 cm (P =0.0011), Spleen metastasis or spleen hilum lesion>1 cm (P=0.0213), colon and mesentery more than one invasion (P=0.006).Conclusion Preoperative CT analyze shows high specificity and sensitivity in detecting high tumor dissemination in advanced ovarian cancer. 5 criteria were identified associated with suboptimal cytoreduction when applied no more than two muiltivisceral procedures.A predictive model was developed for initial treatment strategy.Disclosure Nothing to disclose