Screening US in Patients with Mammographically Dense Breasts: Initial Experience with Connecticut Public Act 09-41
Abstract
In our 1st year offering technologist-performed handheld screening breast US to Connecticut women with dense breasts, the cancer detection rate was 3.2 per 1000 women screened; we also found a high rate of Breast Imaging Reporting and Data System category 3 and 4 lesions, although these rates could be reduced by classifying some nonsimple cysts as benign, without loss in sensitivity.
Purpose
To determine performance and utilization of screening breast ultrasonography (US) in women with dense breast tissue who underwent additional screening breast US in the 1st year since implementation of Connecticut Public Act 09-41 requiring radiologists to inform patients with heterogeneous or extremely dense breasts at mammography that they may benefit from such examination.
Materials and Methods
Informed consent was waived for this institutional review board–approved, HIPAA-compliant retrospective review of 935 women with dense breasts at mammography who subsequently underwent handheld screening and whole-breast US from October 1, 2009, through September 30, 2010.
Results
Of 935 women, 614 (65.7%) were at low risk, 149 (15.9%) were at intermediate risk, and 87 (9.3%) were at high risk for breast cancer. Of the screening breast US examinations, in 701 (75.0%), results were classified as Breast Imaging Reporting and Data System (BI-RADS) category 1 or 2; in 187 (20.0%), results were classified as BI-RADS category 3; and in 47 (5.0%), results were classified as BI-RADS category 4. Of 63 aspirations or biopsies recommended and performed in 53 patients, in nine, lesions were BI-RADS category 3, and in 54, lesions were BI-RADS category 4. Among 63 biopsies and aspirations, three lesions were malignant (all BI-RADS category 4, diagnosed with biopsy). All three cancers were smaller than 1 cm, were found in postmenopausal patients, and were solid masses. One cancer was found in each risk group. In 44 of 935 (4.7%) patients, examination results were false-positive. Overall positive predictive value (PPV) for biopsy or aspirations performed in patients with BI-RADS category 4 masses was 6.5% (three of 46; 95% confidence interval [CI]: 1.7%, 19%). Overall cancer detection rate was 3.2 cancers per 1000 women screened (three of 935; 95% CI: 0.8 cancers per 1000 women screened, 10 cancers per 1000 women screened).
Conclusion
Technologist-performed handheld screening breast US offered to women in the general population with dense breasts can aid detection of small mammographically occult breast cancers (cancer detection rate, 0.8–10 cancers per 1000 women screened), although the overall PPV is low.
© RSNA, 2012
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Article History
Received March 27, 2012; revision requested April 16; final revision received May 18; accepted May 23; final version accepted June 1.Published online: Oct 2012
Published in print: Oct 2012