17% of women with early-stage breast cancer have unnecessary mastectomies, and doctors want to know why

What happens when doctors encourage patients to decide for themselves what kind of cancer treatment they should receive — and then the patients make the wrong choice?

That is the dilemma facing a growing number of surgeons who care for women with early-stage breast cancer, new research suggests.

Survey results from 2,402 women with the disease reveal that misconceptions about the value of surgery lead many patients to remove a healthy breast when there is no medical reason to do so. Patients were more likely to make this decision when their surgeons failed to make clear that the procedure would not reduce the risk that their cancer would come back, or prolong their life.

“When patients participate more in their breast cancer surgical decisions, they more often receive aggressive treatment,” researchers wrote in a study published Wednesday in JAMA Surgery. “Ironically, a physician’s desire to support patient autonomy may result in excessive surgery if patients are misinformed, as our results suggest is common.”

The surgery in question is called contralateral prophylactic mastectomy, or CPM. This is when doctors find cancer in one breast and then remove not just the affected breast but the other one too.

It sounds like a logical way to reduce the risk of breast cancer, but in most cases, it isn’t. Unless a woman has a genetic mutation that increases her risk for the disease, the chance that a patient with early-stage cancer in one breast will later develop it in the other breast is very low — too low, doctors say, to justify the risks that come with surgery. That’s why the American Society of Breast Surgeons advises doctors to steer most women away from CPM.

This wasn’t always the case, but treatments like chemotherapy, immunotherapy and hormone therapy have become so effective that in addition to reducing the risk that the known breast cancer will return, they also make it unlikely that a second breast cancer will develop, the study authors explained.

“No compelling evidence suggests a survival advantage,” they wrote. And yet, “rates of this aggressive, costly, morbid, and burdensome procedure are increasing over time … even among patients without a high genetic risk of a secondary primary breast cancer.”

To understand why this is happening, Dr. Reshma Jagsi, a radiation oncologist at the University of Michigan, and her colleagues sent surveys to 3,880 women in Los Angeles County and Georgia who were diagnosed with stage 0, stage 1 or stage 2 breast cancer between July 2013 and September 2014. The women were identified through registries maintained by the National Cancer Institute. Among the eligible women, 71% responded.

Overall, 44% of the women said they considered removing their healthy breast, including the 24.8% of women who considered it “strongly” or “very strongly,” the researchers found. Women with high-risk mutations were more likely to think about CPM, but even among those with an average risk for breast cancer, 21% gave it strong or very strong consideration and an additional 20% considered it “moderately” or “weakly.”

Among the women who at least contemplated CPM, 38% said they knew the procedure didn’t “improve survival for all women with breast cancer,” according to the study. An additional 24% were under the false impression that it did, and 38% said they didn’t know.

Similarly, 43.5% of these women said they knew that removing a healthy breast “does not prevent cancer from recurring for all women with breast cancer,” while 17% thought it did and 39.5% said they didn’t know, according to the study.

Ultimately, 14% of women with an average risk of breast cancer went through with the surgery, along with 26% of high-risk women. Nearly all (96%) of the women who removed a healthy breast cited “peace of mind” as a reason for doing so — even though many of them had acknowledged that CPM would not reduce the risk that cancer would return or extend their life.

This finding suggests that women “do believe — whether rationally or emotionally — that there is a meaningful effect of more aggressive surgery on the ultimate risk of recurrence or survival,” the study authors wrote. Surgeons should emphasize to patients that they can get the same peace of mind with less drastic types of therapy, they added.

In this study, women were more likely to opt for CPM if they were younger, white, had attended at least some college, had a mother, sister or daughter with breast cancer, had private insurance (instead of Medicaid) or had larger breasts. Also, women in Georgia were more likely to have CPM than women in Los Angeles.

When the researchers used statistical methods to control for each patient’s age and family history of breast cancer, they found that women with a high-risk mutation were only slightly more likely to have the surgery than were average-risk women. In fact, the difference between the two groups was too small to be statistically significant.

A minority of women (37%) said their surgeons recommended against the procedure, and these patients took that advice to heart — only 2% of them got the surgery anyway, the researchers found. On the flip side, 11% of women said their surgeons recommended CPM, and 59% of these patients followed that advice.

An additional 46% of women said their surgeons neither recommended nor discouraged CPM; among this group, 21% had the surgery, according to the study.

The researchers called the results “sobering.” But they also suggest a straightforward way to confront the problem.

“Our findings should motivate surgeons to broach these difficult conversations with their patients, to make their recommendations clear, and to promote patients’ peace of mind by emphasizing” the effectiveness of other treatments, they wrote.

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