Impact of the Peritoneal Surface Disease Severity Score on Survival in Patients with Colorectal Cancer Peritoneal Carcinomatosis Undergoing Complete Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy

In patients with colorectal cancer peritoneal carcinomatosis (CRPC), only patients with a complete cytoreduction will benefit. The current selection criteria are ill-defined. The Peritoneal Surface Disease Severity (PSDS) staging was introduced as a basis of scoring patients into prognostic groups to improve patient selection. This study determines the impact on survival of the PSDS in a cohort of patients undergoing complete cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for CRPC. A retrospective review of two prospective databases of patients with complete CRS and HIPEC for CRPC was performed to score patients on the PSDS. Survival was analyzed using the Kaplan-Meier method. Univariate and multivariate analyses were performed to determine the impact of various clinicopathological factors on survival. There were 56 patients who underwent complete cytoreduction and HIPEC. Of these, 6 patients (11%) were PSDS stage I and median survival (MS) has not been reached, 33 patients (59%) were PSDS stage II and MS was 38 months, 10 patients (18%) were PSDS stage III and MS was 24 months, and 7 patients (13%) were PSDS stage IV and MS was 7 months. Univariate analysis demonstrated the association of clinical symptoms (P = .022), PSDS (P = .002), and tumor histopathology (P = .074) as factors affecting survival. Multivariate analysis demonstrated that PSDS (P = .002) was an independent positive predictive factor associated with survival. In patients with CRPC who undergo a complete cytoreduction and HIPEC, the PSDS staging system has been demonstrated to be an important prognostic indicator. It appears that even with a complete cytoreduction and HIPEC, patients with PSDS stage IV do not benefit from treatment.