BreastScreen Victoria is part of a free national breast cancer screening program available to women from the age of 40 years and targetted at women aged 50-74 years. Women with a suspected abnormality on their screening mammogram are referred for further assessment by clinics such as the Maroondah Reading and Assessment Service (RAS). Ultrasound is a key part of this assessment service.
We have analysed Maroondah RAS assessment services provided to 1,828 clients between March 2014 and June 2016, to characterise the contribution of ultrasound to those services, and identify any patterns in client or disease characteristics where ultrasound has the greatest impact. This cohort was aged 40-88, with 304 women (17%) diagnosed with breast cancer during assessment.
For example:
ï Ultrasound was used for 69% of assessment clients, for 78% of women with a cancer diagnosis at the completion of assessment.
ï Ultrasound was used for 50% of clients where assessment mammography downgraded the RANZCR score to 1 (No specific abnormality).
ï Ultrasound was more likely to be used for women with a higher score at screening mammography (98% with of women referred with RANZCR 5 (Malignant), 75% with RANZCR 4 (Suspicious) and 67% with RANZCR 3 (Equivocal)).
ï Ultrasound use was less common for women with calcifications (19%), slightly more common at first round screening (71%), and more common for women with multiple lesions (81%).
ï Ultrasound use did not differ by age or breast density.
ï Overall correlation between ultrasound and screening mammography scores was moderate (r=0.7, p<0.0001).
ï For women undergoing ultrasound and mammography during assessment, ultrasound had a 64% positive predictive value (RANZCR?3 and a final cancer diagnosis) and a 98% negative predictive value (RANZCR?2 and a benign final outcome).
ï For women with calcifications identified at screening, ultrasound had a positive predictive value of 70% and a negative predictive value of 67%.
ï For all clients referred to assessment with a screening RANZCR 3 (equivocal), cancers were slightly more likely for women with a family history of breast cancer, older women, subsequent screening rounds and higher mammographic breast density.
ï For clients with screening RANZCR 3 (equivocal) and calcifications, cancers were more likely with higher breast density and subsequent round screening, but not family history or age.
We will overview these findings and other results that help characterise the role of ultrasound in BreastScreen assessment services.