Prognostic value of the volume time index (VTI) ratio for patients with appendiceal cancer with peritoneal carcinomatosis treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC).

Abstract

e15704 Background: Completeness of cytoreduction score (CC-score) and tumour volume (as expressed by the peritoneal cancer index (PCI)) have been demonstrated as important post-operative prognostic factors in those patients with appendix cancer with peritoneal metastases undergoing CRS/HIPEC. A previous analysis included a pre-operative factor and demonstrated the tumour marker to volume index (CA19-9/PCI) in patients who had low grade appendiceal cancer with peritoneal metastases was an independent prognostic factor for overall survival (OS). This analysis aims to evaluate VTI as a prognostic factor in low- and high-grade appendix neoplasms with peritoneal dissemination managed with CRS/HIPEC. Methods: A retrospective cohort study of all patients diagnosed with appendiceal cancer with peritoneal dissemination managed with CRS/IPC from 1996 to 2017 was performed by analysing the survival effect of the ratio of tumour volume to the time between initial tumour resection and CRS/HIPEC. VTI was stratified into low versus high groups, and tumour grade was divided into low grade: diffuse peritoneal adenomucinosis (DPAM); and high grade: peritoneal mucinous carcinomatosis (PMCA). Results: Two hundred and sixty-four patients were included. For both DPAM and PMCA, there was no statistically significant difference in overall survival between patients with a low versus high VTI. For both low and high VTI in DPAM, the median survival was not reached, p= 0.586. For PMCA, those with a low VTI had an overall survival of 63 months (95%CI 48-NR), versus those with a high VTI 69 months (95%CI 45-NR), p= 0.97. There was no statistically significant difference in the median recurrence free survival (RFS) between low and high VTI for both DPAM and PMCA. Conclusions: The volume to time ratio for appendix cancer with peritoneal dissemination was not an independent prognostic indicator for overall survival in patients undergoing CRS/HIPEC, suggesting that this index is not a valuable pre-operative planning tool.