Pathologic Distribution Of Disease At The Time Of Interval Debulking Versus Primary Tumor Reduction In Women With Primary Peritoneal, Ovarian, Or Fallopian Tube Carcinoma.

5584 Background: The surgical approach for interval debulking after neoadjuvant chemotherapy (NACT) for primary peritoneal, ovarian, or fallopian tube carcinoma has largely been extrapolated from experience with primary tumor reductive surgery (PTRS). It is unknown whether procedures considered mandatory in PTRS, such as hysterectomy, contribute to comparable removal of macroscopic disease in the NACT setting. Our study compared the difference in pathologic distribution of disease at interval debulking surgery versus primary tumor reduction. Methods: After IRB approval, patients who received NACT or PTRS were identified through the tumor registry and surgical database at a single institution from 2008-2012. Involvement of organs at the time of surgery was categorized as either macroscopic, microscopic and no tumor. Statistical analyses included Wilcoxon Mann-Whitney and Fisher’s exact tests. Results: Of the 163 patients identified, 111 (67%) received NACT and 54 (33%) underwent PTRS. Median age was 62 and the majority of patients had stage IIIC high-grade serous carcinoma (91%). Macroscopic ovarian involvement was more common at time of PTRS (92 % vs 63 %, p <0.001). Gross uterine involvement was significantly less in the NACT group compared to PTRS, with the majority of specimens in the NACT group free of disease (Macroscopic 11 % vs 42%, no tumor 62% vs 44 %, p <0.002). However, 27% of the NACT had microscopic uterine serosal disease. Macroscopic large bowel involvement was 50 % in the PTRS vs 26 % in NACT(p<0.005). There was no difference in disease involvement of the small bowel or omentum. Conclusions: The pathologic disease distribution at the time of interval tumor debulking is significantly different from that encountered during primary cytoreductive surgery.. NACT appears to reduce macroscopic large bowel and uterine tumor involvement and may negate the need for hysterectomy and/or large bowel resection at the time of interval debulking to achieve no gross residual.