MRI in advanced ovarian cancer: multicentre MISSION trial

Background For patients with advanced ovarian cancer, complete cytoreductive surgery (CRS) offers the best chance for long-term survival and cure. Currently, staging relies on CT and, in selected cases, diagnostic laparoscopy, both of which have important limitations. This study assessed the diagnostic performance of MRI for predicting complete interval CRS. Methods This prospective multicentre cohort study included FIGO stage III–IV ovarian cancer patients scheduled for interval CRS. Radiologists, blinded to surgical findings, independently scored the MRI-derived Peritoneal Cancer Index (mriPCI). Gynaecologic oncologists recorded the surgical PCI (sPCI) before and after intraoperative disclosure of MRI findings (revised-sPCI). The primary endpoint was the ability of mriPCI to predict complete interval CRS (no macroscopic residual disease). Secondary endpoints included concordance between mriPCI and sPCI, diagnostic yield from MRI disclosure, and inter-reader agreement. Sample size calculations indicated that 189 patients undergoing interval CRS should be included. Results Between 2018 and 2023, 270 patients were recruited, of whom 194 were eligible for analysis. Complete interval CRS was achieved in 149/194 patients (77%). The diagnostic performance of mriPCI showed an AUC of 0.76 for predicting a complete CRS. The revised-SPCI, after intraoperative disclosure of MRI led to an AUC of 0.88. MRI findings led to a change in sPCI in 19% of patients. Interobserver reliability for mriPCI was substantial (Interclass correlation coefficient 0.81, 95% CI 0.67–0.88). Conclusions MRI enables accurate, non-invasive prediction of complete interval CRS feasibility in advanced ovarian cancer. Integration of MRI into surgical planning enhances intraoperative detection of lesions and can facilitate decision-making, supporting its role as a non-invasive staging tool. Trial registration number NCT03399344.