Background: The peritoneal cancer index (PCI) calculated during exploratory laparotomy is a strong prognostic factor for overall survival (OS) in patients with colorectal peritoneal metastases (PM) who undergo cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). Progression of the PCI between diagnostic laparoscopy (DLS) and potential CRS + HIPEC (Delta PCI) might be a more dynamic prognostic factor for OS after CRS + HIPEC.
Materials and methods: Between 2012 and 2018, all colorectal PM patients who underwent an exploratory laparotomy for potential CRS + HIPEC after DLS were retrospectively identified from a prospectively maintained database. Patients were divided into stable disease (Delta PCI 0-3), mild progression (Delta PCI 4-9), or severe progression (Delta PCI >= 10). Kaplan-Meier analysis and a multivariate Cox regression were performed.
Results: Eighty-four patients (Delta PCI 0-3, n = 35; Delta PCI 4-9, n = 34; and Delta PCI >= 10, n = 15) were analysed. Median OS after CRS + HIPEC was significantly decreased in patients with a Delta PCI of 4-9 (35.1 [95% CI 25.5-44.6]) or Delta PCI >= 10 (24.1 [95% CI 11.7-36.5]) compared to patients with a Delta PCI of 0-3 (47.9 [95% CI 40.0-55.7], p = 0.004). In multivariate regression analysis, Delta PCI remained an independent risk factor for OS: Delta PCI 4-9 HR 3.1 (95% CI 1.4-7.2, p = 0.007) and Delta PCI >= 10 HR 4.4 (95% CI 1.5-13.1, p = 0.007).
Conclusion: A high Delta PCI is an independent dynamic prognostic factor for OS and might reflect a more aggressive tumour biology in patients with colorectal PM. HIPEC surgeons should be aware of a high-Delta PCI-associated diminished prognosis and should reconsider CRS + HIPEC when confronted with a Delta PCI >= 10. (C) 2019 Elsevier Ltd, BASO - The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.