Volume-Time Index Is Not an Indicator of Outcome for Patients Undergoing CRS/HIPEC for Treatment of High-Grade Appendiceal Carcinomatosis

Abstract

Completeness of cytoreduction score (CC-score) and tumour grade have been shown to be independent prognostic factors in patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of high-grade appendiceal carcinomatosis (PMCA). In patients with colorectal cancer with peritoneal metastases (CRPM) that undergo CRS/HIPEC, volume time index (VTI) has been shown to be an independent prognostic factor for overall survival (OS). This analysis was conducted to evaluate VTI as a prognostic factor in PMCA. We performed A retrospective cohort study of 131 patients who underwent CRS-HIPEC for PMCA from 1996 to 2017. VTI was calculated and analyses were performed to determine the association with patients' outcomes. Median overall survival by high vs. low VTI groups were 69 months (95%CI=45-NA) vs. 63 months [95% Confidence Interval (CI)=48-not available (NA)], with an associated difference in 5-year survival rates of 52.1 (95%CI=39.5-68.8) vs. 50.6 (95%CI=35.2-72.6) respectively, with a non-significant p-value of 0.968. For the 82 patients with complete recurrence data, the median RFS stratified by high vs. low VTI were 16 months (95%CI=10-25) vs. 20 months (95%CI=13-34) respectively, with no statistically significant difference in 5-year recurrence-free survival (RFS). VTI for PMCA was not shown to be correlated with overall survival (OS) for patients undergoing CRS/HIPEC, and suggests that the rate of tumour growth does not affect the patients' outcome. Neither high PCI nor rapid tumour growth following primary tumour resection should, therefore, be a contraindication for CRS/HIPEC in patients with PMCA.