Abstract
OBJECTIVE: To test the non-inferiority of extended abdominopelvic ultrasound examination compared with contrast-enhanced computed tomography (CT) and whole-body diffusion-weighted magnetic resonance imaging (WB-DWI/MRI) in discriminating preoperatively between resectable and non-resectable disease based on the European Society for Medical Oncology (ESMO) and European Society of Gynecological Oncology (ESGO)-defined criteria in patients with tubo-ovarian carcinoma. METHODS: The Imaging Study on Advanced ovArian Cancer was a prospective multicenter observational study conducted in five European gynecological oncology centers. All centers had ESGO accreditation to perform advanced ovarian cancer surgery, and ultrasound examinations were performed by a European Federation of Societies for Ultrasound in Medicine and Biology level-III examiner in a standardized manner. Included in the analysis were patients enrolled between 2020 and 2022 with suspected or histologically proven primary tubo-ovarian (including peritoneal) carcinoma who, for the purposes of the study, underwent ultrasound and CT imaging, as well as WB-DWI/MRI if available, prior to surgery. The index tests, which included the preoperative imaging modalities as well as intraoperative exploration at the start of surgery, supplemented by biopsy or follow-up imaging for extra-abdominal locations, evaluated the presence of disease at eight anatomical sites that, if infiltrated, would indicate non-resectability of the tumor according to the ESMO-ESGO criteria. Surgical outcome, described by the surgeons at the end of the procedure, was used as the reference standard and non-resectability was defined as the presence of residual disease > 1 cm or when debulking surgery was not feasible. The area under the receiver-operating-characteristics curve (AUC) and F(1) score were used to assess the performance of the preoperative imaging methods and surgical exploration in discriminating between patients with resectable and those with non-resectable disease, based on the ESMO-ESGO criteria. We also calculated the percentage agreement between imaging findings and surgical exploration findings at the start of surgery, supplemented when applicable by biopsy or follow-up imaging for extra-abdominal locations, regarding the presence of tumor infiltration at each of the eight anatomical sites associated with non-resectability. RESULTS: Of 279 patients enrolled during the study period, 242 were included in the final analysis. In the subgroup of 167 patients who underwent surgery and had been examined by all three imaging methods, the AUC of the three imaging modalities and surgical exploration for discriminating between resectable and non-resectable disease based on the ESMO-ESGO criteria was 0.835 (95% CI, 0.756-0.915) for ultrasound, for CT it was 0.754 (95% CI, 0.664-0.843), for WB-DWI/MRI it was 0.720 (95% CI, 0.626-0.814) and for surgical exploration it was 0.952 (95% CI, 0.915-0.988). Ultrasound was not inferior to CT or WB-DWI/MRI, based on the AUC and F(1) score, in discriminating between patients with resectable and those with non-resectable tubo-ovarian carcinoma. At surgical exploration, at least one non-resectability criterion was present in 32.2% cases. The criteria observed most frequently at surgical exploration were small-bowel involvement (23.6% of cases), diffuse deep infiltration of the root of the small-bowel mesentery (18.2% of cases) and hepatic hilum involvement (5.4% of cases). The percentage agreement between ultrasound and surgical exploration in assessing the presence of disease in at least one of the eight anatomical sites that, if infiltrated, would indicate non-resectability of tumor, was 83.9%, surpassing the percentage agreement with surgical exploration of both CT (77.7%) and WB-DWI/MRI (75.8%). CONCLUSION: When performed by an experienced examiner, ultrasound is not inferior to either CT or WB-DWI/MRI in discriminating between resectable and non-resectable disease in patients with tubo-ovarian carcinoma, based on evaluation of the presence of the disease in at least one of eight anatomical sites that, if infiltrated, would indicate non-resectability of the tumor. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.