Women with a single breast cancer are increasingly having double mastectomies despite evidence that survival is not increased. As noted at the Breast Cancer Symposium, such surgeries account for an estimated 25,000 cases per year. Two studies reported at the meeting and discussed in an ASCO telecast news briefing before the meeting explored some of the ramifications of this trend.
In one (Abstract 71), researchers at the University of Chicago found that 88 of 151 women newly diagnosed with breast cancer (58%) considered having a preventive mastectomy on the healthy breast immediately after the diagnosis, and that many of those women considered it an option even before they were diagnosed with breast cancer.
But those women also had more anxiety about the decision and were also more anxious in general about having cancer elsewhere in their body than women who did not consider the procedure.
A second study, also from the University of Chicago and based on a very large database, found that the actual risk of surgical or medical complications from a double mastectomy is very low (Abstract 62).
In addition to ASCO, the symposium is co-sponsored by the American Society of Breast Surgeons, the American Society of Clinical Oncology, the American Society for Radiation Oncology, the National Consortium of Breast Centers, and the Society of Surgical Oncology.
Decision Before Diagnosis
For the first study, results of a 55-item survey developed at the University of Chicago Survey Lab showed that 38 percent (58) of the newly diagnosed patients had thought about their surgery choice even before diagnosis: 58 percent wanted or considered a contralateral preventive mastectomy as soon as they were diagnosed, while 25 percent knew at that time they did not want that procedure.
Eleven percent said they knew what contralateral prophylactic mastectomy was but did not think it was a possibility for them, and six percent had not heard of it.
“Many newly diagnosed breast cancer patients are undergoing contralateral preventive mastectomy, and we found that more than half were considering contralateral mastectomy at some point in their decision-making process,” said Katharine Yao, MD, Clinical Associate Professor at the University of Chicago Pritzker School of Medicine, Division of Plastic and Reconstructive Surgery, and Director of the Breast Surgical Program at NorthShore University Health System in Evanston, Illinois.
But of the 151 women surveyed, only 12 ultimately chose the double procedure. There were no statistically significant differences in age, race, stage of disease, or family history between the groups who wanted or considered a double mastectomy and those who did not.
Yao and her co-researchers also compared patients' knowledge, perception, and anxiety factors in women who said they considered a contralateral prophylactic mastectomy and those who did not. Among those who wanted or considered contralateral prophylactic mastectomy, 43 percent said they worried “very much or extremely” about getting cancer in other parts of their body, compared with 11 percent of those who said they did not want or consider the procedure.
Women who considered having contralateral prophylactic mastectomy were more likely to rate the diagnostic process as “very/extremely emotionally difficult” (47% vs. 23%), and to state that being diagnosed with breast cancer “sent them into a daze” than those not wanting/considering the procedure (38% vs. 13%). Those who wanted or considered the procedure also had lower knowledge levels about the risk of recurrence, Yao said.
“Many newly diagnosed patients are worried about cancer in the other breast, and they overestimate their risk of getting cancer in the other breast.”
She added that the study points to the need to do a better job of educating women that the risk of developing cancer in the opposite breast is actually low.
Filling Knowledge Gaps
The moderator of the telecast, Harold J. Burstein, MD, MD, PhD, a member of ASCO's Cancer Communications Committee, who is Associate Professor of Medicine at Harvard Medical School and a breast cancer specialist at Dana-Farber Cancer Institute, said he found it striking that so many women think about contralateral prophylactic mastectomy even before diagnosis, and that women who considered it were more anxious about cancer in general and more likely to think that removing the other breast may be important in preventing recurrence.
“Those are knowledge gaps that the collective medical team can help those patients understand,” Burstein said.
“Although we don't know that filling in those gaps would lead people to make different decisions and there's no doubt that personal preference is still highly important for women to feel comfortable about the choices they make, understanding that these women come in with perhaps a slightly different knowledge base or more concerns, and addressing them as part of a multidisciplinary effort, would be very important.”
Medical Complication Rate Same for Single, Double Mastectomy
The other study showed that medical complications from double mastectomy are infrequent and not affected by whether a woman has a single or double mastectomy. However, implant failure or a need for re-operation or an additional unexpected operation within 30 days or bleeding requiring transfusion were found to be more frequent.
Speaking at the news briefing, the study's senior author, Mark Sisco, MD, Clinical Assistant Professor at the University of Chicago Pritzker School of Medicine, Division of Plastic and Reconstructive Surgery, said that while each woman will interpret the findings differently, they should be discussed with everyone. The first author was Amanda Kathryn Silva, MD, who presented the results of the poster study at the meeting itself.
Data were taken from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP), a 400-hospital database that quantifies 30-day risk-adjusted surgical outcomes. The researchers reviewed data on 18,229 surgeries, representing 11,727 single and 6,502 double mastectomies (Unlike the case of Angelina Jolie [OT, 10/10/14 issue]—these women all did have a breast cancer.
The results showed that the rate of implant loss was 54 percent higher with double mastectomy (0.7% vs. 1.0%); transfusion after implant reconstruction was 119 percent higher (0.3% s. 0.8%); and transfusion after the less common tissue reconstruction was 124 percent higher with double mastectomy (3.4% vs. 7.9%).
But re-operation after implant was only 13 percent higher (6.8% vs. 7.6%), Sisco said. And there was no difference in medical complications, including heart attack, pneumonia, kidney failure, stroke, urinary tract infection, or blood clots—these occurred less than one percent of the time,” he emphasized.
The data on implants are significant, since approximately 80 percent of women undergoing mastectomy have an implant, he noted.
Quantifying Risks for Patients
Burstein said that the key point is that the rate of serious complications remains quite low for both single and double procedures, but at the same time some complications do increase, particularly for implant removals.
“This is some of the first data we have seen that allows the surgical team to quantify for a woman who is deciding between single or double mastectomy what exactly the risk of the larger, double operation might be. That's why it is so important for multidisciplinary groups to be aware of these data and for the patients to be able to be counseled so they really understand the risks of the procedure they are getting into.