A recent study adds to accumulating evidence that ultrasonography can help diagnose cancer in women with dense breasts.
Researchers analyzed data from 2,809 women from across the United States, Canada and Argentina. All of the women analyzed had dense breasts in addition to one other risk factor for breast cancer. About 40% of women 40 years old and older have dense breast tissue.
Each woman in the study had three screenings over three years with mammography and ultrasonography. There were about 111 breast cancers found. About 80% of the cancers were invasive.
Both tests identified about the same number of cancers, with 129 women needing an ultrasound or 127 women needing a mammography for doctors to find one cancer.
Although both methods spotted about the same number of cancers, the study found that more cancers detected on mammography were milk duct carcinomas in suite while more cancers seen on ultrasounds were invasive breast cancers.
Mammography was more efficient at picking up cancers with calcifications. Calcifications are characteristic of ductal carcinoma in situ. Ductal carcinoma in situ is the most common noninvasive form of breast cancer.
Ductal carcinoma in situ may spread and become invasive cancer, however, it is not life-threatening on its own. Some researchers question whether it should be called cancer and treated at all.
On the other hand, ultrasound was better at detecting invasive cancers and those without calcifications. Cancers found on ultrasound will make a bigger difference than those we find in mammography.
Unfortunately, ultrasound also produced more false positives. During the first year, 9% of biopsies that were ordered based on ultrasound findings confirmed a cancer diagnosis. In comparison about 29% of biopsies confirmed a cancer diagnosis for mammograms.
The study recommends a complementary test for women with dense breast tissue.