EP23.43: Imaging prediction of borderline and invasive mucinous ovarian tumours

To assess the accuracy of preoperative CT scans in differentiating between borderline and invasive mucinous ovarian tumours. We extracted information using electronic patient records from preoperative imaging reports, clinical notes and MDT outcomes for women with borderline or invasive mucinous ovarian tumours treated at a North-West London gynecology cancer centre. We recorded patient age, histological diagnosis, size of the largest ovarian mass, and whether the mass was predicted to be borderline or invasive cancer on imaging. 112 cases were identified between 2013 and 2023. The median age was 52 years (range 22-94 years) and the median size of ovarian mass in the group was 19.5cm. Based on postoperative histology, there were 64 cancers and 48 borderline ovarian tumours (BOTs). The sensitivity, specificity, positive and negative predictive values of preoperative CT scan for distinguishing mucinous ovarian cancer from borderline tumours were 79.49%, 61.11%, 81.58% and 57.89% respectively. From 64 patients with cancer, we excluded 25 on the basis that we had no access to the reports, there were no comments on the diagnosis, or they did not have a CT scan. Of the remaining 39 patients, 31 were correctly predicted to have cancer on CT scans. Of 7 patients with cancer who did not have a preoperative CT, 3 had an MRI scan and 4 an ultrasound (US). None of these scans predicted cancer in this group. There were 48 patients with a diagnosis of BOT. 30 patients were excluded on the same basis as above. Of the remaining 18 patients, 10 were correctly predicted to have BOT on CT. Of the patients with BOT who did not have a CT, 5 had an MRI scan and 4 of these correctly predicted BOT. 7 had preoperative US scans: 2 correctly predicted a diagnosis of BOT, and 5 were reported as benign. We have reported one of the largest datasets for mucinous borderline and invasive ovarian tumours. We have shown that, for these large tumours, in a “real-life” setting, CT scan has acceptable accuracy in distinguishing invasive from borderline ovarian mucinous tumours.