Women who undergo certain types of breast cancer surgery may be more likely to face subsequent surgeries, according to a new study published in the Journal of the American Medical Association.
Researchers found that nearly one in four women who undergo lumpectomies for breast cancer treatment end up having follow-up surgery to remove additional tissues. This procedure is known as a re-excision. But that rate of second surgeries varies greatly among surgeons and hospitals, researchers found.
Breast conservation surgery is one of the most common cancer surgeries performed in the United States. It is intended to remove cancerous and pre-cancerous tumor tissues while keeping the maximum aesthetic appearance of the breast.
Because of today's advances in chemotherapy, hormone treatment and radiation, many women do not need the entire breast removed. Instead, doctors are able to remove only the tumor and surrounding tissue, while preserving the breast itself.
But surgeons cannot know if the entire tumor has been removed until it is put under a microscope. Once the tumor is removed, a pathologist examines the rim of the tissue, known as a surgical margin, to be sure that it is free of cancer cells. A margin free of cancer cells is known as a "clear margin."
While effective, this process leaves the door open to the possibility that patients will have to go under the knife a second time to remove the rest of the cancerous tissue.
Researchers from Michigan State University analyzed data obtained from patient and medical records of more than 2,200 women who underwent a partial mastectomy. They found that more than 20 percent of the patients had to return for follow-up surgery to remove more tissue from the affected breast.
The second operation rates varied greatly among surgeons (from 0 percent to 70 percent) and institution (1.7 percent to 20.9 percent).
Authors suggest that there should be clearer literature that allows for comprehensive criteria on what is a "clear margin" of breast tissue.
"It appears there is a wide variation in how surgeons go about performing second operations following a partial mastectomy," said senior study author Dr. Laurence E. McCahill of the Richard J. Lacks Cancer Center in Grand Rapids, Mich. "About two-thirds of breast cancer patients will undergo a lumpectomy and about one-quarter will undergo a second operation."
Dr. Jay Harris, professor and chair of the department of radiation oncology at Harvard Medical School in Boston, said there is large variability in how much of a margin is needed.
Nevertheless, "the evidence is quite clear that for invasive cancer you only need two millimeters of clear margin, but many [surgeons] places aim for greater margins," Harris said.
Newer approaches to cancer treatments take several years to filter into general clinical practice -- and this could be one of the reasons for the varying statistics, said Dr. Daniel Kopans, professor of radiology at Harvard Medical School.
"There is a great deal of art involved in breast surgery and there is also a great deal of variation between cancers," Kopans said.
There are several questions that are left unanswered from the study, including the size of the cancers, whar kind of imaging was used to guide the surgery, and how the cancers were found, he said.
"The authors should have tried to understand the reason for the variation rather than just report it," Kopans said.