Radiological assessment of Peritoneal Cancer Index on preoperative CT in ovarian cancer is related to surgical outcome and survival

Abstract

Purpose: To evaluate whether Peritoneal Cancer Index (PCI) assessed on preoperative CT (CT-PCI) can be used as non-invasive preoperative tool to predict surgical outcome, disease-free survival (DFS) and overall survival (OS). Materials and methods: This is a retrospective, observational cohort study performed in a single institution. We considered all patients with diagnosis of ovarian cancer and preoperative CT, who had undergone upfront cytoreductive surgery between 2008 and 2010 and had post-operative clinical follow-up to December 2015. Two radiologists reviewed CT scans and assessed CT-PCI using Sugarbaker’s diagram. We assessed the discriminatory capacity of the CT-PCI score on the surgical outcome by ROC curve analysis. DFS and OS were assessed by Kaplan–Meier nonparametric curves and by multivariable Cox-regression analysis. Results: A total of 297 patients were included in the present analysis. CT-PCI was positively correlated with post-operative residual disease [odds ratio (OR) 1.04, 95% CI 1.01–1.07, p = 0.003]. ROC curve analysis returned AUC = 0.64 for the prediction of total macroscopic tumour clearance. In multivariable analysis, patients with no peritoneal disease seen on CT had a significantly longer DFS [Hazard ratio (HR) 2.28, p = 0.007]. Radiological serosal small bowel involvement was an independent predictor for shorter OS (HR 3.01, p = 0.002). Conclusion: Radiological PCI assessed on preoperative CT is associated with the probability of residual disease after cytoreductive surgery; however, it has low performance as a triage test to reliably identify patients who are likely to have complete cytoreductive surgery. CT-PCI is positively correlated with both DFS and OS and may be used as an independent prognostic factor, for example in patients with high FIGO stages.