The Accuracy of the Surgical Peritoneal Cancer Index in Patients with Peritoneal Metastases of Colorectal Cancer.

INTRODUCTION

The peritoneal cancer index (PCI) is one of the most important prognostic factors in patients with peritoneal metastases from colorectal cancer undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). The PCI is determined during laparotomy by 2 experienced surgeons and plays a major role in the decision to proceed with CRS-HIPEC. The primary objective of this study was to determine the accuracy of the surgical PCI (sPCI) by comparing it with the PCI confirmed by the pathologist (pPCI).

METHODS

All consecutive patients who underwent CRS-HIPEC for colorectal peritoneal metastases between February 2015 and June 2018 were identified. Relevant patient- and tumor-related characteristics were collected.

RESULTS

In total, 119 patients were included, 60 males (50.4%). The median age was 64 (IQR 55-71). The median sPCI (sPCI = 11, IQR 6-16) was significantly higher than the median pPCI (pPCI = 8, IQR 3-13, p < 0.001). The total pPCI was lower than the total sPCI in 80 patients (67.2%). In 21 patients (17.6%), the sPCI was overestimated with ≥5 points. Small lesions are more likely to be negative. In patients that underwent resection of their primary tumor prior to CRS-HIPEC, the difference between the sPCI and pPCI was significantly larger (p < 0.05).

CONCLUSIONS

Surgical calculation of the PCI often results in overestimation. Far-reaching consequences are tied to the macroscopic evaluation of the sPCI, but this evaluation seems not very reliable.