EP30.11: Two‐step strategy for optimising the diagnosis of borderline ovarian tumours

To determine the diagnostic accuracy of a two-step system for the classification of borderline (BOT) ovarian tumours. Ambispective diagnostic accuracy study based on ultrasound data collected at a University Hospital with a gynecologic oncology unit between 2012 and 2022. Two IOTA-certified level III sonographers classified adnexal masses using the IOTA ADNEX system (first step) and the presence of borderline ovarian tumours (BOTplus) characteristics like: Low level of echogenicity content, vascularisation in the papilla found, and pattern of microcystic tissue that resembles a group of small bubbles (second step). The main outcome was the correct classification of BOT. Histopathology was used as the diagnostic reference standard. For analysis, the diagnostic performance of the two-step strategy was estimated. A diagnostic precision analysis was performed. 73 adnexal masses were included in the study as they were classified by IOTA ADNEX as BOT (first step). Of these, 32 (44%) had a low level of echogenicity content, 28 (38%) had vascularisation in the papilla found, and 24 (33%) had a pattern of microcystic tissue that resembles a group of small bubbles. 27% (20/73) corresponded to BOT by histopathology. The diagnostic yield for the first step had a sensitivity of 71%, specificity of 67%, Positive Predictive Value (PPV) of XX%, and Negative Predictive Value (NPV) of 93%. Diagnoses that can cause confusion: mesothelial cyst, immature teratoma, hemorrhagic cyst, cystadenofibroma, and Müllerian cysts. Regarding the diagnostic performance of the two-step strategy, it had a sensitivity of 77%, specificity of 71%, PPV of 32%, and NPV of 95%. In our experience, the diagnostic accuracy of the two-step system (IOTA ADNEX + BOTplus) is superior to the risk stratification for BOT conferred by IOTA ADNEX.