Patients with high breast density do benefit from a technology that enables surgeons to assess whether cancer cells remain on the margins of excised tissue during breast conserving surgery, known as a lumpectomy, according to a UCI Health study.
“A positive margin on the main specimen of removed tissue means that some of the tumor may have been left behind during surgery,” said UCI Health surgical oncologist Karen Lane. “A clear margin is a rim of healthy tissue surrounding the tumor, which indicates all of the cancer has been removed.”
The study findings were presented in September 2015 at the American Society of Clinical Oncology Breast Cancer Symposium in San Francisco, by Lane and surgical oncologist Erin H. Lin, DO.
Failure to achieve clear margins is a leading cause of reoperation in the treatment of early-stage breast cancer, as well as breast cancer recurrence.
Higher breast density poses increased risk
Dense breast tissue contains a higher percentage of glandular and fibrous tissue than fatty breasts, which makes it more difficult for tumors to be detected during a mammography. With higher breast density, surgeons and patients also face an increase in risk that not all of the cancer has been removed during a lumpectomy.
When this happens, which surgeons refer to as a positive margin, he or she takes or “shaves” more tissue. This additional removed tissue is called a shaving. The goal of a lumpectomy is to remove all cancer while conserving as much healthy breast tissue as possible.
Intraoperative margin assessment
Lin and Lane performed surgery using MarginProbe, a device that allows the surgeon check the tumor and quickly determine whether all of the cancer has been removed or if additional shavings need to be taken. Traditionally, patients had to wait days for the results of a pathology test to determine whether all of the cancer was removed, increasing the possibility of reoperation.
The UCI Health study, entitled “Intraoperative margin assessment with the MarginProbe at different mammographic breast densities,” analyzed the results of the 196 patients from the MarginProbe Pivotal Trial in which the device was used and for whom breast density data was available.
As breast density increases, so does clinical benefit
The study found that breast density does not adversely affect the performance of MarginProbe in determining whether all cancer was removed during the lumpectomy. More positive margins on the main specimen and the number of shavings increased in denser breasts, but the average volume of shavings did not increase as breast density increased.
“Our study results suggest that, unlike mammography, as breast density increases, the MarginProbe’s effectiveness in assessing margins improves, resulting in a better breast operation, Lane said.