RT Journal Article SR Electronic T1 EPV222/#603 Radiological response to neoadjuvant chemotherapy as indicator of optimal cytoreduction in advanced ovarian cancer JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A117 OP A117 DO 10.1136/ijgc-2021-IGCS.293 VO 31 IS Suppl 4 A1 S Maricic A1 A Mandic A1 N Prvulovic Bunovic A1 S Stojanovic A1 I Stojic A1 N Stanulovic YR 2021 UL http://ijgc.bmj.com/content/31/Suppl_4/A117.2.abstract AB Objectives The extent of tumor cytoreduction (residual tumor volume) is the most important prognostic factor in advanced ovarian cancer (AOC). Neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) is an option in cases where optimal cytoreduction is not possible in upfront surgery. Despite that NACT did not raise the survival rate, it still showed increased cytoreduction rate, decreased surgical morbidity and good progression-free interval. The purpose of this study is to determine the role of imaging in the prediction of the extent of cytoreduction after NACT.Methods The 37 patients with AOC were included in the study. They were operated in our center after the administration of NACT. Evaluation of the response to NACT was done with CT/MRI after 3–4 cycles of NACT.Results NACT was administered in 3 or 4 cycles of Paclitaxel/Carboplatin protocol. Patients were diagnosed in FIGO stage III (29; 78,4%) or IV (8; 21,6%). Cytological (26; 70,3%) or histopathological (9; 29,7%) confirmation of malignancy was done prior chemotherapy. According to imaging, 32 subjects (86,5%) achieved a partial response (PR) to chemotherapy, 4 of them (11,8%) obtained complete response (CR) and one retained stable disease (2,7%). Out of those subjects with PR, 19 (59,4%) had optimal debulking, while 13 (40,6%) had a suboptimal debulking procedure. All 4 of the patients with CR had complete debulking, while one with SD had suboptimal debulking.Conclusions Imaging evaluation of response to NACT is a valid method to assess surgical resectability and select patients appropriate for complete cytoreduction.