Introduction/Background RCOG guidelines recommend using RMI or IOTA simple rules (IOTA-SR) for assessment of ovarian masses. IOTA-SR characterise ovarian masses by using 5 benign and 5 malignant features. A mass with both or neither is deemed as inconclusive. A literature review showed a dearth of guidance on management of inconclusive ovarian masses.

Barts Trust implemented IOTA-SR in managing ovarian masses in 2019. Face to face teaching of sonographers took place between 09/2018 – 09/2019 with refresher sessions every six months.

Methodology We manually identified ultrasound reports with words ‘inconclusive’ or ‘indeterminate’ between 09/2019 and 01/2021. All women with inconclusive masses were included, records were reviewed to identify the use of IOTA simple rules template and quality of reporting.

Results We screened – reports, 142 cases were identified, and IOTA-SR were used in 43%. 81 were referred by primary care and 54 were two-week wait referrals. 73 patients had further imaging (USS in 23%, MRI in 74%, CT in 3%). 54% patients were discharged, 19% had ongoing follow up and 17% had surgery. Of the women that had surgery, 12 had benign pathology, 6 had borderline cysts and 6 had invasive cancer.

Conclusion As less than half of the women had an IOTA-SR scan, we will continue to roll out IOTA teaching and make the ultrasound template easier to use. Management pathway to be refined, disseminated and re-audit prospectively.

Disclosures None