BSUR/BMUS Position Statement on Ultrasound Risk Stratification of Adnexal Lesions

13th Nov 2026

Adnexal lesions are a common finding on pelvic ultrasound, and accurate characterisation is essential to support the timely diagnosis of ovarian cancer while avoiding unnecessary investigation and intervention for benign disease.

In recent years, validated risk stratification systems such as IOTA-ADNEX and O-RADS Ultrasound have demonstrated improved diagnostic performance and provide structured approaches to reporting and management. As national organisations consider future updates to ovarian cancer and imaging guidance, it is important that recommendations reflect the available evidence, accessibility of training, and the realities of UK clinical practice.

To better understand current practice, BMUS/BSUR surveyed 102 NHS professionals involved in adnexal ultrasound assessment, including sonographers, radiologists, advanced nurse practitioners and gynaecologists working across district general hospitals, tertiary centres, community diagnostic centres and independent NHS providers.

Significant variation in practice was identified. Of the 90 respondents using structured assessment systems, 42% reported using IOTA Simple Rules, 41% O-RADS Ultrasound and 6% IOTA-ADNEX. When managing indeterminate or complex lesions, respondents most commonly sought advice from experienced sonographers (48%) or radiologists (44%), with 13% referring directly for multidisciplinary team discussion.

BSUR and BMUS support the routine use of validated structured ultrasound risk stratification for adnexal lesions across the NHS and believe that national guidance should move beyond the Risk of Malignancy Index (RMI) towards contemporary, evidence-based approaches. To support safe, effective and equitable implementation, BSUR and BMUS recommend that national guidance should include the following:

• Use a validated structured risk stratification system, such as IOTA-ADNEX or O-RADS Ultrasound, without mandating a single model
• Recognise the role of specialist imaging review and MRI in indeterminate lesions.
• Involve NHS sonographers and radiologists as key stakeholders in the development and implementation of future guidelines.

The survey findings summarised within this statement are considered alongside a comprehensive review of the available evidence and a detailed analysis of UK practice, presented in an accompanying manuscript is being prepared for submission.