RT Journal Article SR Electronic T1 333 Impact of extent of cytoreductive surgery (CRS) on survival in epithelial ovarian cancer (EOC), primary peritoneal carcinomatosis (PPC), and fallopian tube cancer (FTC) at the american university of beirut (AUBMC) JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A138 OP A138 DO 10.1136/ijgc-2019-IGCS.333 VO 29 IS Suppl 3 A1 M Seoud A1 A El Housheimi A1 I Jaafar A1 K Hamed A1 F Jamali A1 R Abdallah A1 A Khalil YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_3/A138.1.abstract AB Objectives To study the impact of the extent of CRS [complete Debulking (CD), optimal Debulking (OD)<1cm, or suboptimal Debulking (SOD) >1cm residual disease] on progression free (PFS) and overall survival (OS) in advanced EOC, PPC and FTC treated at AUBMC 1998–2018.Methods We retrospectively reviewed all patients with advanced disease who underwent either Primary debulking surgery (PDS) or if they had large tumor burden/multiple co-morbidities/poor performance status, they received neoadjuvant chemotherapy and interval debulking surgery (NACT+IDS).Results Of 300 patients with EOC/PPC/FTC, 220 had advanced stages (IIIB-IV). 66.4% had CD, 29.7% OD and 2.6% SOD. Results are shown in image 1 and tables 2 and 3. Median survival is expressed in months. In stage IIIC, CD led to a significantly higher PFS compared to OD (image 1) (P-value=0.015). However, this increase in PFS was only seen after IDS (table 2) (P-value in IDS=0.009). Once a CD was reached, There was no statistically significant increase in PFS regardless of timing of CRS (Image 3) (Pvalue=0.775). OS was not affected by extent of CRS (Image 1).View this table:Abstract 333 Figure 1 Extent of CRS and PFS and OS in stages IIIC and IVView this table:Abstract 333 Table 1 CD in the primary versus interval setting in stage IIICView this table:Abstract 333 Table 2 PFS of patients with CD in PDS versus IDS in stage IIICConclusions The extent of CRS significantly prolonged PFS but not OS in stage IIIC but not IV. This increase in PFS is only seen after IDS. Patients having CD have similar PFS and OS regardless of the timing of CRS.