The CEA/PCI ratio is a superior prognosticator than mCOREP for colorectal cancer patients with peritoneal carcinomatosis.

ABSTRACT

Background: The CEA/PCI ratio, which evaluates tumour marker and burden, has been demonstrated as a prognosticator for patients with colorectal cancer with peritoneal carcinomatosis. The aim of this study was to compare the CEA/PCI ratio with the Modified Colorectal Peritoneal Score (mCOREP) for overall survival (OS) and recurrence free survival (RFS). There is no literature currently comparing both markers for RFS. Methods: Data was collected retrospectively for patients undergoing CRS and hyperthermic intraperitoneal chemotherapy (HIPEC) at the Peritonectomy Unit at St. George Hospital, NSW from January 2015 to December 2021. Results: From 187 patients, an increase in CEA/PCI ratio was associated with reduced OS (p < 0.01) and RFS (p < 0.01), whereas mCOREP score did not demonstrate such association with OS (p = 0.5) nor RFS (p = 0.4). However, CEA/PCI ratio greater than the median of 0.63 was correlated with an increased OS (p = 0.01), whereas the mCOREP greater than the median of 4 correlated with reduced OS (p < 0.01). Median mCOREP also demonstrated association with reduced RFS in patients with PCI <15 (p = 0.03), whereas CEA/PCI ratio above 0.63 demonstrated association with reduced RFS in patients with PCI ≥ 15 (p = 0.02). Conclusion: The CEA/PCI ratio is more associated with OS and RFS in patients with colorectal cancer with peritoneal carcinomatosis, when compared with mCOREP. CEA/PCI ratio above 0.63 was correlated with increased OS, whereas mCOREP above 4 is correlated with reduced OS. CEA/PCI ratio above 0.63 demonstrated reduced RFS for patients with higher PCIs. By contrast, mCOREP >4 illustrated reduced RFS in patients with lower PCIs.