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

Background/aim: 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.

Patients and methods: 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.

Results: 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).

Conclusion: 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.