Concordance of laparoscopic and laparotomic peritoneal cancer index using a two-step surgical protocol to select patients for cytoreductive surgery in advanced ovarian cancer.

Purpose: The aim of our study was to assess concordance of staging laparoscopy and cytoreductive surgery (CRS) peritoneal cancer index (PCI) when applying a two-step surgical protocol. We also aimed to evaluate the accuracy of diagnostic laparoscopy to triage patients for complete cytoreduction, and to define optimal time between staging laparoscopy and CRS.

Methods: We designed a retrospective review of prospectively collected data from patients with advanced ovarian cancer who underwent a diagnostic laparoscopy followed by a CRS a few weeks later (two-step surgical protocol), from January 2010 to April 2019. Only patients selected for complete cytoreduction, and with available PCI score from both surgeries were included. PCI concordance was assessed using intraclass correlation coefficient (ICC).

Results: During the study period 543 patients underwent a laparoscopic staging for ovarian carcinomatosis. Among them, 43 patients fulfilled inclusion criteria. ICC between laparoscopic and laparotomic PCI was 0.54. After applying the linear regression equation: laparoscopic PCI + 0.2 x [days between surgeries] + 2, ICC increased to 0.79. Completeness cytoreduction score and laparoscopic PCI were significantly associated (OR 1.27, 95% CI 1.03-1.57, p = 0.03). AUC of laparoscopic PCI to predict complete cytoreduction was 0.90.

Conclusion: Concordance between laparoscopic PCI assessment and PCI score at the end of CRS is fair within a two-step surgical management. Laparoscopic assessment underestimates final PCI score by two points, and this difference increases with the delay between both surgeries. Diagnostic laparoscopy can adequately select patients for CRS, and optimal time to perform it is no more than 10 days after laparoscopy.