OP14.10: External and temporal validation of the ultrasound‐based endometriosis staging system (UBESS): a diagnostic accuracy study

To externally and temporally validate the ultrasound-based endometriosis staging system (UBESS) to predict the level of complexity of laparoscopic surgery for endometriosis. A multicentre retrospective diagnostic accuracy study was carried out between 2016 and 2018. Four different centres with advanced ultrasound and laparoscopic services were recruited (one for temporal validation and three for external validation). UBESS I, II and III were correlated with the Royal College of Obstetricians and Gynaecologists (RCOG) surgical stages 1, 2 and 3. Comparison between temporal and external sites as well as each site was performed in terms of the diagnostic accuracy of UBESS. 294/317 women were included in the final analysis. UBESS overall accurately classified 80%, 71% and 60% of women to RCOG levels 1, 2 and 3 respectively (table 1). When ureterolysis without bowel surgical cases (n=54) were excluded, the sensitivity of UBESS to correctly classify RCOG level 3 increased from 60% to 96.4% (p < 0.005). UBESS externally validated did not perform as well as expected. When however the cases of ureterolysis (RCOG 3) in the presence of a normal ‘deep endometriosis’ scan were excluded, the performance of UBESS improved dramatically. These findings justify the search for other ultrasound markers to predict superficial pelvic side wall disease. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.