Assessment of peritoneal metastases with DW-MRI, CT, and FDG PET/CT before cytoreductive surgery for advanced stage epithelial ovarian cancer.

BACKGROUND: Preoperative assessment of peritoneal metastases is an important factor for treatment planning and selection of candidates for cytoreductive surgery (CRS) in primary advanced stage (FIGO stages III-IV) epithelial ovarian cancer (EOC). The primary aim was to evaluate the efficacy of DW-MRI, CT, and FDG PET/CT used for preoperative assessment of peritoneal cancer index (PCI).

MATERIAL AND METHODS: In this prospective observational cohort study, 50 advanced stage EOC patients were examined with DW-MRI and FDG PET/CT with contrast enhanced CT as part of the diagnostic program. All patients were deemed amenable for upfront CRS. Imaging PCI was determined for DW-MRI, CT, and FDG PET/CT by separate readers blinded to the surgical findings. The primary outcome was agreement between the imaging PCI and PCI determined at surgical exploration (the reference standard) evaluated with Bland-Altman statistics.

RESULTS: The median surgical PCI was 18 (range: 3-32). For all three imaging modalities, the imaging PCI most often underestimated the surgical PCI. The mean differences between the surgical PCI and the imaging PCI were 4.2 (95% CI: 2.6-5.8) for CT, 4.4 (95% CI: 2.9-5.8) for DW-MRI, and 5.3 (95% CI: 3.6-7.0) for FDG PET/CT, and no overall statistically significant differences were found between the imaging modalities (DW-MRI - CT, p = 0.83; DW-MRI - FDG PET/CT, p = 0.24; CT - FDG PET/CT, p = 0.06).

CONCLUSION: Neither DW-MRI nor CT nor FDG PET/CT was superior in preoperative assessment of the surgical PCI in patients scheduled for upfront CRS for advanced stage EOC.