CHICAGO — Using a new ultrasound technique, researchers involved in a single-center effort think they may have found a new diagnostic technique that could cut down on the number of breast biopsies performed in the U.S.
Using "elasticity" imaging, researchers correctly identified both cancerous and benign lesions in nearly all of the cases they studied, they reported at this year's meeting of the Radiological Society of North America (RSNA; Oak Brook, Illinois) at McCormick Place.
The researchers describe elasticity imaging as a non-invasive modification of a routine ultrasound exam. It involves the analysis of tissue movement and how soft or stiff it may be. For example, on the ultrasound — which uses a standard probe — if a lesion is stiff it will show up as black on the ultrasound screen. If it is soft, it will show up as white on the screen.
"In our work, elasticity imaging has been found to have high specificity," said Richard Barr, MD, PhD, professor of radiology at Northeastern Ohio Universities College of Medicine and radiologist at Southwoods X-Ray and MRI (both Youngstown). "If our results can be reproduced in a large, multicenter trial, this technique could significantly reduce the number of breast biopsies required."
Breast biopsies are the source of considerable discomfort and stress for women, and in some studies have been associated with increasing the risk for moving a breast tumor from the benign to cancerous category. And of the 1.4 million breast biopsies performed each year in the U.S., 80% of breast lesions biopsied are found to be benign, Barr said, citing figures from the American Cancer Society (ACS; Atlanta).
The ACS estimates that 212,920 women will be diagnosed with breast cancer in the U.S. this year. While mammography is the standard breast cancer screening exam, it leads to many false positives and thus unnecessary biopsies.
One presenter earlier in the conference reported that diagnostic accuracy of mammography is only about 66%.
Barr said that screening with MRI or ultrasound may be more effective for high-risk patients with dense breast tissue. However, although these modalities find more breast lesions than mammography, MRI and ultrasound have low specificity, meaning they are less effective at distinguishing which lesions are malignant, which are benign.
In a study of 163 lesions identified and scheduled for biopsy in 99 patients, Barr used a "real-time, free-hand" elasticity imaging technique in correlation with a typical ultrasound exam.
Of those lesions, 106 were found to be benign and 17 malignant. And of these, 105 had an "elastogram" that measured less than 1, according to Barr's method of scoring, indicating benign. And of the 17 malignant lesions, all but one had an elastogram larger than 1.
In the study, Barr and colleagues selected those lesions to score if a lesion appeared larger on the elastogram than it did on the ultrasound, and the researchers called it cancerous. If it appeared smaller, they called it benign.
He said that the position of the probe on the ultrasound "does not appear to change results."
Barr acknowledged that his group is not the first to study elasticity imaging. Still, these new results indicate a positive predictive value of 94% and specificity of 99%.
"There is the potential for us to significantly reduce the number of biopsies performed," he said.
Barr also said that he understood from the beginning of his studies that if such a technique were going to be accepted, the results would have to be fast, simple and reproducible.
Barr also said that as of last week, Siemens Medical Solutions (Malvern, Pennsylvania) has secured FDA 510(k) clearance for the procedure on its ultrasound device, the instrument that Barr used in his studies.
While the technique doesn't have a CMS reimbursement code as a new methodology, Barr said he expects that elasticity imaging is likely to be "bundled in with the cost of mammograms."
Barr and his colleagues are planning to expand their research in an international, multicenter trial beginning in January.
In another RSNA presentation, researchers reported that a CT scan may be more accurate than a standard mammogram — and much less uncomfortable — in detecting breast cancer.
The researchers from the University of Rochester (Rochester, New York) reported that the new scan produces 3-D pictures, which are better at showing whether a spot on the X-ray is a benign lesion or a tumor.
It can also provide pictures of tissue around the ribs and outer breast toward the armpit, where 50% of cancers are found.
The cone beam breast CT scanner takes 360-degree views of breast anatomy, with no need to compress the breast between cold glass plates.
"We have one case in which a cancer shows up phenomenally well using this new imaging system, whereas when you look at the same lesion on a mammogram, it is hard to detect," said Avice O'Connell, MD, director of women's imaging at the University of Rochester's Medical Center.
O'Connell's team is still doing trials and will not have a full study until 60 women have undergone the imaging.