Cytoreduction (Peritonectomy Procedures) Combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Advanced Ovarian Cancer: Retrospective Italian Multicenter Observational Study of 511 Cases

PURPOSE: The aim of this study was to help with the process of selecting patients with advanced ovarian cancer to undergo cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) by analyzing outcome data at distinct clinical time points reflecting the natural history of the disease. METHODS: In a retrospective Italian multicenter study investigating patients with advanced ovarian cancer who underwent CRS plus HIPEC between 1998 and 2014, we analyzed data for consecutive patients at eight treatment time points: primary debulking surgery (PDS); interval debulking surgery after partial response, after no response, and after a pathologic complete response to neoadjuvant chemotherapy; first recurrence with a progression-free interval >12, <12 months, or >12 months in patients who underwent further chemotherapy before CRS and HIPEC; and patients who underwent two or more CRS procedures and chemotherapy lines before CRS and HIPEC. RESULTS: The 511 enrolled patients underwent 3373 procedures; 72.6% achieved complete cytoreduction, with an overall major morbidity of 17.4%. At a median follow-up of 53.8 months, overall survival (OS) was 54.2 months (95% confidence interval [CI] 44–58.4) and progression-free (PFS) survival was 16.6 months (95% CI 14.7–19.1). Outcome analysis in patients in whom CRS plus HIPEC was used for primary advanced cancer or recurrent ovarian cancer showed significant differences in OS and PFS according to the time points analyzed. Multivariate analysis identified completeness of CRS, Peritoneal Cancer Index, and the times when patients underwent CRS plus HIPEC as independent prognostic factors. CONCLUSIONS: This selective information on survival should help in interpreting the findings from ongoing randomized studies focusing on CRS plus HIPEC in patients with advanced ovarian cancer.