Novel prognostic score for outcomes after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal cancer with metachronous peritoneal carcinomatosis

Background This study aimed to determine pre‐ and peri‐operative parameters with significant predictive value for post‐operative outcomes in patients with recurrent colorectal cancer presenting as peritoneal carcinomatosis undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS‐HIPEC), and to develop a novel prognostic scoring system for prediction of survival outcomes. Methods A single‐institution review of prospectively collected data from all patients who underwent CRS‐HIPEC between October 2005 and October 2017 was conducted. Univariate and multivariate analyses were used to identify significant parameters for prediction of post‐CRS‐HIPEC disease‐free survival and overall survival (OS). Results A total of 278 patients underwent CRS‐HIPEC, of whom 72 were for peritoneal carcinomatosis from recurrent colorectal cancer. Disease‐free interval (DFI; P = 0.006), peritoneal cancer index (PCI; P = 0.001) and left upper quadrant disease ( P = 0.023) were significant independent predictors of 3‐year OS. DFI (0.007), PCI ( P  < 0.001) and intraoperative blood loss (BL; P = 0.001) were significant independent predictors of 5‐year OS. PCI and BL were significant independent predictors of both 3‐year ( P = 0.026, PCI; P = 0.009, BL) and 5‐year ( P = 0.002, PCI; P = 0.011, BL) disease‐free survival. Predictive models were developed for risk stratification of OS. Conclusion PCI, DFI, left upper quadrant disease and BL have significant predictive value for post‐CRS‐HIPEC outcomes. Risk stratification models allow for more prudent patient selection and ultimately more accurate prognostication of post‐operative outcomes.