Monday, January 4, 2016
Breast Ultrasound & Mammography May Be Equally Effective
“It looks like ultrasound does better than mammography for node–negative invasive cancer,” said study leader Dr. Wendie Berg, professor of radiology at Magee-Women’s Hospital of UPMC in Pittsburgh. Node-negative invasive cancer is cancer that hasn’t invaded the lymph nodes, but has grown past the initial tumor, according to the U.S. National Cancer Institute.
“The downside [to ultrasound] is, there were more false positives,” Berg said.
At least one expert doesn’t expect this study to change current screening practice in the United States.
“For U.S. patients, what [this study] really confirms is, ultrasound should be used as a supplemental screening exam in dense breast patients,” said Dr. Lusi Tumyan, a radiologist and assistant clinical professor at the City of Hope Cancer Center, in Duarte, Calif. She reviewed the findings but was not involved in the study. “At this time we do not have enough data to support or refute ultrasound as a screening tool for average-risk patients,” Tumyan said.
The study was published Dec. 28 in the Journal of the National Cancer Institute.
Ultrasound is generally used as a follow-up test once a potential breast tumor has been discovered through a mammogram or a physical exam, according to the American Cancer Society (ACS). The ACS says that ultrasound is a valuable tool that’s widely available and noninvasive.
The new study involved 2,600 women living in the United States, Canada and Argentina who had ultrasound and mammogram annually for three years. They had no symptoms of breast cancer at the study’s start, but they did have dense breast tissue – considered a risk factor for breast cancer – plus at least one other risk factor for breast cancer.
At the end of the study, 110 women were diagnosed with breast cancer. Detection rates were similar between the two tests. Rates of false-positive results (where the scan erroneously suggests a tumor) were higher for ultrasound, the researchers reported.
The findings suggest that for women who don’t have a high risk of breast cancer but have dense breasts, “we find many more cancers if we do ultrasound in addition to mammography,” Berg said.
Guidelines about breast cancer screening vary among organizations. Current ACS guidelines advise women to consider beginning screening at age 40, depending on individual risk factors. Then undergo annual screening with mammography from ages 45 to 54. At age 55, the ACS suggests continuing annual screening with mammography or switch to screening every two years, depending on risk factors.
Ultrasound is non-invasive, but mammography is invasive. We know that x-ray exposure is a major factor in causing cancer because the ionizing radiation causes cell mutation. Dense breast tissue actually absorbs more radiation from x-ray than less dense tissue.
Why not use the non-invasive tool as primary detection? This is just another example of medical reversal – research shows how we can do it better, but it contradicts past medical thinking. Therefore, it’s easier to stick with the dogma, than admit you were wrong.
The Bottom Line:
I believe women should alternate between ultrasound and thermography, both non-invasive, for annual testing. MRI is also another non-invasive option, but is much more expensive than any other imaging study.
Source: December 28 2015 National Institutes of Health