Strategies for Managing Intraoperative Discovery of Limited Colorectal Peritoneal Metastases

Background: Management of limited synchronous colorectal peritoneal metastases (CRPM) is critical to outcome. Resection of the primary tumor and CRPM can be performed concurrently, followed by hyperthermic intraperitoneal chemotherapy (HIPEC) either immediately, during the same procedure (one-stage), or during a systematic second-stage procedure (two-stage). Objective: The aim of this study was to compare these two strategies for morbidity, mortality, and survival. Methods: All patients presenting with limited (initial Peritoneal Cancer Index [PCI] ≤ 10) synchronous CRPM who had undergone complete cytoreductive surgery plus HIPEC between 2000 and 2016 were selected from a prospectively maintained institutional database. Results: Overall, 74 patients were included—31 in the one-stage group and 43 in the two-stage group. During second-stage surgery, a peritoneal recurrence was diagnosed in 37 (86%) patients, 12 of whom had a PCI > 10 (28%) and 2 of whom had unresectable disease (5%). Among the one-stage group, peritoneal recurrence occurred in 29% of patients after a median delay of 23 months. Overall survival at 1, 3, and 5 years was similar between the two groups, i.e. 96%, 59%, and 51% for the one-stage group, and 98%, 77%, and 61% for the two-stage group. A PCI > 10 at the time of HIPEC, as well as liver metastases, were independent negative prognostic factors. Conclusions: For incidental limited CRPM diagnosed during primary tumor resection, one-stage curative treatment is preferable, avoiding a supplementary surgical procedure. Given the critical issues associated with completeness of resection, patients should be referred to centers specialized in peritoneal surgery.