Influence of modern systemic therapies as adjunct to cytoreduction and perioperative intraperitoneal chemotherapy for patients with colorectal peritoneal carcinomatosis: A multicenter study

Background: To evaluate the role of modern systemic therapies and its role as palliative or curative therapy for patients with colorectal peritoneal carcinomatosis with an emphasis on patient selection with the colorectal Peritoneal Surface Disease Severity Score (PSDSS). Methods: From three specialized treatment centers, patients with colorectal peritoneal carcinomatosis were identified between December 1988 to December 2009 to receive best supportive care, standard, or modern systemic therapies. Intent was classified as palliative or curative (if treated by cytoreductive surgery combined with perioperative intraperitoneal chemotherapy). Patients were stratified according to the PSDSS. Survival was estimated by the Kaplan-Meier method. Results: Palliative and curative treatment achieved a median survival of 9 (95% confidence interval [95% CI] 5.9-12.8) and 38 (95% CI 30.2-45.2) months, respectively (P < 0.001). The type of chemotherapy in the palliative and curative group influenced outcome (P < 0.001, P = 0.011, respectively). In the palliative group, PSDSS I/II had a median survival of 24 (95% CI 15.6-32.6) and PSDSS III/IV had a median survival of 6 (95% CI 4.9-8.0) months (P < 0.001). In the curative group, PSDSS I/II had a median survival of 49 (95% CI 40.0-58.3) and PSDSS III/IV had a median survival of 31 (95% CI 20.4-40.9) months (P = 0.002). Conclusions: Modern systemic therapies were associated with improved outcome in patients with colorectal peritoneal carcinomatosis treated systemically alone or with cytoreductive surgery combined with perioperative intraperitoneal chemotherapy. Preoperative evaluation with the PSDSS may improve patient selection and optimize outcomes.