Ultrasound imaging appears to perform similarly with mammograms in detecting breast cancer, according to new research.
This diagnostic tool’s detection rate was found comparable to that of mammography, the standard for breast cancer testing. This is deemed good news for women living in developing countries with typically greater access to ultrasound than mammography.
This new finding was published Dec. 28 in the Journal of the National Cancer Institute.
“[I]t looks like ultrasound does better than mammography for node-negative invasive cancer,” reported study lead author Dr. Wendie Berg, radiology professor at the Magee-Womens Hospital of UPMC in Pittsburgh.
According to the U.S. National Cancer Institute, node-negative invasive cancer is a form of cancer that has not entered the lymph nodes but has gotten past the initial tumor.
Berg added, however, that there were more false positives with ultrasound.
Study Method And Findings
The study included 2,600 females in the United States, Canada and Argentina who had ultrasounds and mammograms annually for three consecutive years. While they exhibited no breast cancer symptoms at the beginning of the trial, they had dense breast tissue, deemed a factor for the disease, as well as one other risk factor.
Upon the interpretation of different radiologists of each of the two scans, 100 women were diagnosed with the cancer. Detection levels were similar between the two testing methods, but false-positive rates were higher for ultrasound than for mammogram.
The team discovered that 32 percent of more than 2,500 women without cancer were asked to return for additional testing at least once after they had an ultrasound, versus the 23 percent who had mammograms.
Berg said the issue is what cancers are most needed to be found, which are the invasive and node-negative ones – what most ultrasounds were finding.
The American Cancer Society (ACS) said that ultrasound typically serves as a follow-up exam once a possible breast tumor is discovered via a physical exam or mammogram. It is considered a highly accessible and non-invasive technique.
Ultrasound and mammography also have comparable costs.
Breast Cancer Screening Guidelines
Prevailing breast cancer screening guidelines differ from one organization to another, with the ACS recommending women to consider screening at age 40 depending on their risk factors.
Based on the ACS, annual mammograms are advised from ages 45 to 54. Once they reach 55, females are urged to continue annual screening or switch to every two years. Women with a family history of cancer or other risk factors are told to also be tested with MRIs.
Insurance coverage for ultrasound also varies from one state or insurance company to another.
According to Dr. Lusi Tumyan of the City of Hope Cancer Center, California passed a law requiring radiologists to inform patients if they have dense breasts, but does not require insurance firms to shoulder supplemental testing. Other states may require insurance companies to pay for additional screening.
Will These Findings Rock The Boat?
Experts do not think this new research will change current breast cancer screening practices.
Tumyan said that it only confirms ultrasound’s position as a supplemental exam in those with dense breasts. "At this time we do not have enough data to support or refute ultrasound as a screening tool for average-risk patients," she argued.
Berg explained that more cancers will be detected for women without breast cancer but have dense breasts if ultrasound will be performed in addition to mammogram.
The main takeaway? Women are encouraged to discuss their risks with their physician, and decide together on which screening test is the best fit for them.
In the United States, about one in eight women or 12 percent are projected to develop invasive breast cancer in their lifetime, with about 232,000 new cases to be diagnosed this year. About 40,000 women are estimated to die from the condition, which remains the second leading cause of cancer death among women.