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2022-RA-891-ESGO Preoperative assessment of non-resectability in patients with ovarian cancer using imaging (ISAAC study) – an interim analysis
  1. Patrícia Pinto1,
  2. Valentina Chiappa2,
  3. Juan Luiz Alcazar3,
  4. Dorella Franchi4,
  5. Antonia Carla Testa5,
  6. Lil Valentin6,
  7. David Cibula1 and
  8. Daniela Fischerová1
  1. 1Gynecologic Oncology Center, Department of Obstetrics and Gynecology, First Faculty of Medicine and General University Hospital, Charles University, Prague, Czech Republic
  2. 2Gynaecologic Oncology, National Cancer Institute of Milan, Milan, Italy
  3. 3Obstetrics and Gynecology, Clínica Universidad de Navarra, Pamplona, Spain
  4. 4Preventive Gynecology Unit, Division of Gynaecology, European Institute of Oncology IRCCS, Milan, Italy
  5. 5Woman and Child Health, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Università Cattolica del Sacro Cuore Roma, Rome, Italy
  6. 6Obstetrics and Gynecology, Skåne University Hospital Malmö, Lund University, Malmo, Sweden


Introduction/Background The aim of the European multicentric prospective study (ISAAC study, Imaging Study on Advanced ovArian cancer) was to test the non-inferiority of abdomino-pelvic ultrasound compared to computed tomography (CT) and whole-body diffusion-weighted magnetic resonance imaging (WB-DWI/MRI) in prediction of surgical outcome in patients with ovarian/tubal/peritoneal cancer.

Methodology All consecutive patients, with suspected ovarian cancer planned for surgery underwent preoperative prediction of non-resectability with ultrasound, CT and WB-DWI/MRI at 5 european centres. The prediction of non-resectability was based on the European Society of Gynecologic Oncology (ESGO) criteria of non-resectability. Findings were compared to the reference standard (surgical outcome).

Results The interim analysis looked at data of the first 59 patients enrolled between 01/2020 and 07/2021. They underwent ultrasound and CT (n=59), and WB-DWI/MRI (n=50). Among them, 83% (49/59) had advanced-stage and 17% (10/59) had early-stage ovarian cancer. Diagnostic laparoscopy only was performed in 12% (7/59) of the cases. In the remaining 88% (52/59) laparotomy was performed with no residual disease at the end of surgery (R0) in 75% (39/52), residual disease ≤1 cm in 10% (5/52) and residual disease >1 cm in 15% (8/52). The ultrasound imaging was non-inferior neither to CT (p-value =0.029) nor to WB-DWI/MRI (p-value = 0.036). Regarding the prediction of resectability, ultrasound obtained the best results with an AUC of 0.85, sensitivity of 91.3% and specificity of 85.7%. CT and WB-DWI/MRI had similar results regarding AUC and sensitivity (0.79 vs 0.78 and 88.6% vs 87.5%), with lower specificity for CT (68.8% vs 86%).

Conclusion This interim analysis represents the first prospective study documenting that ultrasound is not inferior to CT and WB-DWI/MRI in predicting the non-resectability of patients with ovarian cancer. ESGO criteria are easy to apply in preoperative imaging without a need for more complex scoring system.

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