5530 Background: In January 2001, we initiated a programatic change in our primary surgical approach to advanced ovarian carcinoma utilizing extensive upper abdominal procedures as needed to achieve maximal cytoreduction. The objective of this study was to determine the impact of incorporating these procedures on overall survival in advanced ovarian, fallopian tube, and primary peritoneal carcinomas. Methods: Two groups of patients (pts) with stage IIIC and IV ovarian, tubal, and primary peritoneal carcinoma were identified for comparison. Group 1, the control group, consisted of all 168 pts who underwent primary cytoreduction between 1/96 and 12/99. Group 2, the study group, was composed of all 209 pts who underwent primary surgery between 1/01 and 12/04, during which time a more comprehensive debulking of upper abdominal disease was used, including diaphragm peritonectomy/resection, splenectomy, distal pancreatectomy, liver resection, resection of porta hepatis tumor, and cholecystectomy. Results: Comparison between the 2 groups revealed no significant difference in age, BMI, performance status, stage, tumor grade, proportion with primary ovarian cancer, preoperative CA-125 levels, preoperative platelet counts, percentage with ascites, or type of postoperative primary chemotherapy. The only 2 variables that differed significantly between the 2 groups were percentage of pts who had extensive upper abdominal surgery and percentage of pts cytoreduced to ≤1 cm residual disease (RD). Patients in Group 2 were more likely to have undergone extensive upper abdominal procedure(s) (37% vs. 1%; P <0.001). Cytoreduction to RD ≤1 cm was achieved in 50% of Group 1 pts compared to 80% of Group 2 pts (P <0.01). Overall median survival was significantly improved in Group 2 versus Group 1 pts (58 vs. 43 mos, [P=0.042], respectively). Conclusions: The recent incorporation of extensive upper abdominal surgical procedures to increase the rate of primary cytoreduction to residual disease ≤1 cm resulted in significantly improved overall survival. A paradigm shift toward more complete primary cytoreduction can improve survival for pts with advanced ovarian, fallopian tube, and primary peritoneal carcinomas. No significant financial relationships to disclose.