Widely varying rates of repeat breast cancer surgery among surgeons: Study

By Dr. Ananya Mandal, MDFeb 1 2012

According to a new study the number of repeat surgeries in women who had a breast tumor removed depends on their individual surgeons and medical centers and no clear reason for these differences are found.

Almost one in four women who get breast-conserving “lumpectomy” surgery undergo another operation to ensure no malignant cells remain, according to a report in the Journal of the American Medical Association. Nearly half of those women had no conclusive evidence of lingering or relapsing cancer, the data showed.

Lead researcher Laurence McCahill, director of surgical oncology at the Lacks Cancer Center in Grand Rapids, Michigan said, “There continues to be considerable variation in how we deliver health care based on individual opinion rather than strong evidence…In an ideal world, there would be a greater degree of logic or evidence as to why someone would undergo a second operation.” “The number of operations women undergo definitely depends on where you’re treated, and even to a greater level on which surgeon you see,” Dr. McCahill said. “We put the math behind it and said this is a lot of second operations that maybe don’t make a difference.”

For the findings the investigators tracked 2,206 women with invasive breast cancer who elected to undergo a lumpectomy. The researchers used electronic medical records for patients treated from 2003 to 2008 at the University of Vermont, Kaiser Permanente in Colorado, Group Health in western Washington and the Marshfield Clinic in Wisconsin to conduct the study.

Lumpectomy is the most common operation for breast cancer, and is performed in 60 percent to 75 percent of the more than 200,000 new cases per year in the United States. It began coming into use about 30 years ago as a means of sparing women from what had been the standard treatment, mastectomy, removing the entire breast. Major studies begun in the 1970s transformed the field by showing that in most cases, women who had lumpectomy plus radiation lived just as long as those who had mastectomies.

The need for additional surgery after a lumpectomy can extract a financial and psychological cost, the researchers said. Of those women who got a repeat operation, one-third had a mastectomy, which entails complete removal of the breast. While some surgeons didn’t do any repeat surgeries on women whose tests were inconclusive, others brought back 70 percent of patients, the research found.

The inconsistency is a challenge, said Shawna Willey, director of the Betty Lou Ourisman Breast Health Center at Georgetown University Hospital in Washington, who wasn’t involved in the study. Willey said she tells patients that as many as 40 percent of women may need a second surgery.

One problem for doctors is determining if the surgeon removed all the cancer, Willey said in a telephone interview. Currently, physicians put six different colors of ink around the extracted tumor, then study it under a microscope to see how close the malignant cells are to the edge. While some are satisfied if there are no signs of cancer on the rim, called a clear or negative margin, others want a bigger zone of safety, she said.

“What’s the definition of a clear margin? We have whole conferences discussing that,” she said. “It would be nice if all practitioners in the breast cancer field could arrive at a consensus of what a negative margin is. That’s one reason we see so much variability among surgeons.”

Fourteen percent of women with cancer at the edge of the extracted tissue didn’t undergo a repeat operation, known as a re-excision, the researchers said. While previous work found positive margins increase the risk that the cancer will return, no studies have shown how large a cancer-free rim is needed to reduce the risk. Removing additional tissue in women with no remaining signs of cancer hasn’t been shown to influence recurrence rates, they said.

Dr. Monica Morrow, the chief of breast surgery at Memorial Sloan-Kettering Cancer Center in New York, said, “It is getting to be the time for leaders in radiation oncology and surgery to get together and make a consensus statement that could help to guide their membership.” The findings show why tissue margins shouldn’t be used to evaluate the quality of surgical care for breast cancer, said Monica Morrow and Steven J. Katz, from the University of Michigan’s department of health management and policy in Ann Arbor.

Morrow and Katz wrote in an editorial that the study didn’t take into account the reasons for returning to the operating room. Some physicians may have low rates because they offer breast-conserving surgery only to patients with tiny tumors that are easiest to remove, leaving others to get an unnecessary mastectomy. It can also be avoided by removing large amounts of normal breast tissue, with a poor cosmetic result, they said. “Uncertainty about the link between process and patient health outcomes underscores the challenge of determining ‘which rate is right,’” they wrote. Providing retreatment rates for individual doctors “may result in greater use of mastectomy as surgeons restrict breast-conserving surgery to patients for whom negative margins are easily achieved.”

The study was funded by the U.S. National Institutes of Health.

Doctors cautioned that it would be a mistake to look for surgeons with a low rate of repeat operations. Dr. Susan K. Boolbol, the chief of breast surgery at Beth Israel Hospital in Manhattan, cautioned that a low rate could mean the surgeon usually did the operation right the first time — but could also mean the surgeon did a lot of mastectomies, or failed to operate again after lumpectomy even when more surgery was needed.