Prognostic impact of intraoperative peritoneal cytology in interval debulking surgery for pelvic high‐grade serous carcinoma

Abstract Background and Objectives The aim of this study was to determine whether peritoneal washing cytology (PWC) during interval debulking surgery (IDS) could predict the prognosis of patients with pelvic high‐grade serous carcinoma (HGSC) achieving R0 status. Methods Between January 2007 and May 2018, 110 patients with ovarian/tubal/primary peritoneal HGSC received platinum‐based neo‐adjuvant chemotherapy, followed by IDS at National Cancer Center Hospital, Japan. All the patients achieved R0 debulking status, defined as no macroscopic residual tumor in the peritoneal cavity at the completion of IDS. PWC was performed before debulking during IDS. The survival outcomes were compared between the PWC‐positive and PWC‐negative groups. Results The median progression free survival (PFS) for the entire cohort was 17 months (range, 5‐133 months). The median PFS for the PWC‐positive group was significantly shorter than that of the PWC‐negative group (16 vs 19 months, HR 2.04, 95% CI 1.22‐3.41, P‐value