Oncologists are often faced with a very difficult decision: whether to follow the science and insist on an evidence-based recommendation for therapy, or acquiesce to a patient's wish to do what they think will make them feel better, even as it contradicts published studies or even guideline-recommended care.
That is the question faced by an increasing number of breast cancer physicians as they treat women with disease in one breast who are convinced that they should have both breasts removed, despite a lack of evidence that it will do anything to improve their survival.
The number of contralateral prophylactic mastectomies performed in North America is increasing by more than 14% a year.
Whereas prophylactic double mastectomy in women at high risk of developing life-threatening breast cancer at a young age is an accepted procedure, performing contralateral prophylactic mastectomy in lower-risk women who already have the disease is much more controversial, not least because it exposes women to a markedly increased risk for complications compared with breast-conserving approaches.
Yet some estimates have suggested that the number of contralateral prophylactic mastectomies performed in North America is increasing by more than 14% a year.
How is it that the number of contralateral prophylactic mastectomies is rising steadily year by year, despite the best efforts of clinicians to persuade women to opt for less radical treatments?
The Guidelines Are Clear
When it comes to the settings in which bilateral mastectomy may be appropriate, the guidelines are consistent.
For example, the National Comprehensive Cancer Network guidelines state, in the March 2018 update to the Clinical Practice Guidelines on Oncology,[1] that women with a known or suspected genetic predisposition to breast cancer "may be considered for prophylactic bilateral mastectomy for risk reduction."
Although the panel singles out women with breast cancer aged 35 years or younger and carriers of BRCA1/2 mutations as candidates, it underlines the importance of counseling and multidisciplinary consultations, as well as a discussion of the associated risks.
Moreover, the panel says that contralateral mastectomy in a women already diagnosed with unilateral breast cancer and treated with mastectomy is "discouraged," whereas performing the operation in a similar woman treated with lumpectomy is "strongly discouraged."
The American Society of Breast Surgeons goes further,[2] saying that "with the possible exception of BRCA carriers," contralateral prophylactic mastectomy "does not appear to be associated with a survival benefit." They say that the procedure should be reserved for women at the highest risk for contralateral breast cancer, namely those with BRCA1/2 mutations and those with a lifetime risk for breast cancer of more than 25%, as well as those who have undergone mantle-field radiation.
On the other hand, "average-risk" women, in whom the risk for breast cancer in the healthy breast is 0.1%-0.6% per year, should be "discouraged" from having contralateral prophylactic mastectomy because they "do not derive any oncologic benefit." They emphasize not only that the operation doubles the risk for surgical complications versus treating only the breast cancer, but also that it "may negatively affect oncologic outcomes" by delaying adjuvant therapy or discouraging women from undergoing radiation therapy.
The Society of Surgical Oncology Breast Disease Working Group agrees, pointing out that there is a lack of reliable evidence to support the use of contralateral prophylactic mastectomy.[3] High-risk women should therefore be counseled on alternative management strategies, including chemoprevention and surveillance imaging, it says. Nevertheless, the group acknowledges that the decision "must be individualized," because "there is no formula for predicting whether the patient will achieve peace of mind."
The Evidence Supports the Guidelines
Of note, the guidelines recommendations are not based simply on expert opinions or consensus discussions, but on large data sets from dozens of studies. For example, prophylactic mastectomy in women with a BRCA1/2 mutation or in those with a family history of breast cancer is backed up by numerous investigations showing that the risk of developing breast cancer is reduced by at least 90% after the procedure.[4,5,6,7]
In contrast, a recent large registry study demonstrated that for women already diagnosed with cancer in one breast, there is no improvement in survival from having both breasts removed.
As reported by Medscape, the analysis of almost 19,000 Californian women diagnosed with stage 0-III unilateral breast cancer showed that bilateral mastectomy was not associated with a mortality difference compared with breast-conserving surgery plus radiation.
Moreover, a Cochrane review of 39 studies involving almost 7400 women,[8]indicated that there was "insufficient evidence" to suggest that contralateral prophylactic mastectomy improved survival, and concluded that bilateral prophylactic mastectomy "should be considered only among those at very high risk."
And the Doctors Agree
As a result of this overwhelming consensus, clinicians speak with one voice.
Lisa A. Newman, MD, director of the Breast Oncology Program at the Henry Ford Health System in Detroit, Michigan, told Medscape that for women with a BRCAmutation, bilateral prophylactic mastectomy can be a "worthwhile" option, because it can reduce the lifetime risk for breast cancer from 40%-85% to less than 10%.
Steven A. Narod, MD, of the Women's College Research Institute at Women's College Hospital in Toronto, Ontario, Canada, emphasized that the procedure nevertheless needs to be performed early, typically between 25 and 30 years of age. "Once you hit 30 [years of age] with a BRCA mutation, your risk starts to become, on an annual basis, pretty big, so if you're going to do it, there's no scientific rationale to wait beyond 30," he said.
For women already diagnosed with breast cancer, Newman said that contralateral mastectomy can be "very effective as the most aggressive strategy available to prevent breast cancer" in the other breast, reducing the risk by up to 95%. She pointed out that this, however, "does not provide a guarantee against future breast cancer," because women can have microscopic breast tissue in the surrounding areas of the body, such as the chest wall or the underarm region.
Furthermore, the overall lifetime risk of developing breast cancer in an "average-risk" woman is 12%. Prophylactic mastectomy reduces that to 2%, which, Newman said, does not outweigh the risks and psychosocial impact of the procedure.
She also underlined that early, conservative breast cancer treatment is successful in the majority of cases, making it unlikely that having prophylactic mastectomy would result in an additional survival benefit.
In other words, as Ashu Gandhi, MD, PhD, an executive member of the UK's Association of Breast Surgery, summarized, "In the family history/BRCA group, there's a justified reason for removing healthy breasts, but in the [lower-risk] group—the 'woman next door' group—there's no clinically justifiable reason to remove both breasts."
Yet the Numbers Keep Growing
Despite all the guidelines recommendations and data from large-scale studies, there is "definitely no question" that there has been a "growing trend of having bigger surgery" over the past 15 years, said Nora Jaskowiak, MD, an associate professor of surgery and surgical director of the Breast Center at University of Chicago Medicine, Chicago, Illinois.
"Usually, that bigger surgery is having a bilateral mastectomy," she told Medscape, adding, "Every single week, patients who could save their breast, get radiated, and do very, very well choose instead to have bilateral mastectomy."
This impression is borne out by a recent analysis of data on more than 230,000 US women, which showed that younger women are increasing likely to choose bilateral mastectomy plus immediate breast reconstruction rather than breast-conserving surgery, regardless of how they respond to neoadjuvant chemotherapy.
As reported by Medscape, rates of bilateral mastectomy with immediate reconstruction increased significantly between 2010 and 2014, from 8.0% to 13.2%, even while rates of pathologic complete response to neoadjuvant chemotherapy rose from 33.3% to 46.3% over the same period.
The analysis referred to earlier of 19,000 women with early-stage breast cancer underlined this trend, with the proportion of women undergoing bilateral mastectomy increasing from 2.0% in 1998 to 12.3% in 2011, or an annual increase of 14.3%.
In both studies, the rates of bilateral mastectomy rose fastest in women aged less than 40 years. All of this is despite studies showing that undergoing bilateral mastectomy can have serious consequences for women.
A study in over 18,000 women reported by Medscape showed that compared with unilateral, or single, mastectomy, contralateral prophylactic mastectomy is associated with a significantly increased risk for implant loss, a greater need for transfusion and reoperation, and longer hospital stays.
Another analysis of almost 600 women followed up around 2 years indicated that contralateral mastectomy was also linked to an increased risk for superficial nipple necrosis, wound breakdown, and infections requiring oral antibiotics, as well as an increased risk for implant exposure.[9]
Although women undergoing contralateral prophylactic mastectomy may have increased breast satisfaction from having both reconstructed at the same time, one systematic review of 22 studies suggested that the procedure can affect sexual well-being and somatosensory function.[10] Specifically, Frost and colleagues[11] found in a survey of over 480 women that contralateral prophylactic mastectomy can have adverse effects on body appearance, femininity, and sexual relationships, affecting between one quarter and one fifth of women.
Even women at high risk for breast cancer who under bilateral prophylactic mastectomy can experience psychological issues, with one study suggesting that around one half feel self-conscious, less sexually attractive, and dissatisfied with the scars.[12]
Why Do Women Choose Bilateral Mastectomy?
So why are women opting to have invasive surgery, such as contralateral prophylactic mastectomy, placing themselves at risk for adverse effects and worse psychological outcomes when the overall benefit could be as much, if not greater, with less invasive treatments?
"People have been looking at this a lot over the past 10 years," Jaskowiak said, "and I think there are a lot of different factors."
One study of almost 3000 women suggested that independent predictors of undergoing contralateral prophylactic mastectomy include white race, being aged less than 50 years, having undergone MRI at diagnosis, the availability of immediate breast reconstruction, and a previous unsuccessful attempt at breast conservation.[13]
Another study, including more than 3600 women, suggested that having contralateral prophylactic mastectomy was linked to a higher educational level, a family history of breast cancer, and the availability of private medical insurance, alongside younger age and white race.[14]
In their study of almost 1500 women, Hawley and colleagues[15] added undergoing genetic testing, regardless of whether the result was positive or negative, to the factors associated with contralateral prophylactic mastectomy, alongside a greater worry about recurrence. This latter finding was supported by a focus group study of women with stage 0-III breast cancer aged less than 40 years, which revealed that women who chose contralateral prophylactic mastectomy were often worried about a future breast event, despite having a low risk.[16]
Narod told Medscape that although genetic testing and the increasing acceptance of bilateral mastectomy as a procedure have both fueled its growth, the reason that has had "the most profound impact is that we've scared women so much."
"There's this high level of baseline anxiety—they're so concerned about daily living under the stress of anxiety that mastectomy is the best way to relieve it," he said. "In other words, there's lots and lots of women out there—and I've seen plenty of them in my clinic—who are being told they have a high risk for cancer, whether it's from a BRCA1 mutation, whether it's from single-nucleotide polymorphisms, whether it's from mammographic density, whether it's from not having kids."
They consequently feel that "it's a matter of time, which translates into this free-floating anxiety, which translates into sleeplessness and some depression, and...other than psychotherapy or drugs, the best cure for that is bilateral mastectomy," Narod added.
Jaskowiak agreed: "Some women are so scared of breast cancer that even if you tell them it's not going to change their survival, they don't want ever to go through what they've just gone through...an abnormal mammogram, additional tests and biopsies, and all that. They want to do anything they can to avoid having to go through all that stuff again."
"I think there's no question that MRI has played a role in this," she said, pointing out that even if the results come back negative, the scrutiny of the other breast and the pain of the procedure is off-putting to women.
Everybody in the chat room says I should just have a bilateral mastectomy.
Jaskowiak believes that social media has also played a role in women choosing contralateral mastectomy. "So many people tell me, 'Oh, well, I went into a breast cancer chat room, and everybody in the chat room says I should just have a bilateral mastectomy.'"
"I don't know how many times I've been told by women about Angelina Jolie, and I have to remind them that they're not Angelina Jolie, that they don't have a mutation, and she never had cancer in the first place," she added.
Yet should anxiety reduction be considered an indication for contralateral prophylactic mastectomy?
Speaking to Medscape, Gandhi said that "the woman might say, 'Well, it doesn't matter to you, but for me it'll make a big difference.'" However, the question of performing mastectomy as a form of anxiety reduction "then becomes not scientific but philosophical," he said.
"If we're reducing the anxiety, then is that not good? On the other hand, we're falsely reducing the anxiety because it has no effect on their prognosis; therefore, it's bad."
Regardless, Gandhi said that "the science is quite secure, but it's very difficult to convince people of that, or it can be, depending on which patient you're dealing with."
Can the Trend Be Reversed?
For Gandhi, it is clear that the drift toward ever more contralateral mastectomies is something the medical profession "definitely should" be trying to counter.
The medical profession should be trying to do what's scientifically true.
He said that "scientifically, it's the right thing and the medical profession, at least, should be trying to do what's scientifically true."
However, how that should be achieved is another question.
Jaskowiak said that "this is something that all breast surgeons are struggling with," adding that it will take "a lot of time and a lot of education," involving not just surgeons but also nurses and other staff on the surgical team.
She cited the example of Katharine Yao at NorthShore University HealthSystem in Evanston, Illinois, who has developed a visual decision-making tool to explain risk. "You can tell people that they have a 2.5% chance of getting a breast cancer in their opposite breast in the next 10 years," said Jaskowiak, "but if they see these hundred people and only two of them are lit up, that sometimes ends up helping people."
Gandhi agreed that education is key, saying that more and more people should be told that it makes no difference. However, he feels that "the doctor telling them at the point of diagnosis is probably the least desirable point."
"If they can hear about it before ever having a diagnosis of breast cancer, that would be much better," he said.
One strategy Jaskowiak believes could help reduce the number of bilateral mastectomies is to be more selective about which patients undergo MRI, and another would be if insurance companies reduced the payment for them. "But it doesn't seem very patient-centered to have this figured out by insurance companies," she said. "It seems like doctors should be able to talk to people and educate them."
In the United Kingdom, for example, the rate of increase in contralateral mastectomies has been consistently lower than that in the United States.
Catherine Priestley, a clinical nurse specialist at the charity Breast Cancer Care in London, United Kingdom, said that it may be assumed that "it's got something to do with our healthcare system and the fact that the National Health Service hasn't got the financial resources to do those sorts of things."
"Actually, the decisions are not driven by finance; they're driven by the risk and benefit to somebody as an individual," she said.
"We make a lot of effort in the United Kingdom to dissuade the woman, and one of the reasons for that is, to put it very brutally, we're not paid per case," Gandhi said. "In a healthcare environment where you're paid per case, although ethically you should be giving the correct medical information, there's a part of you that may not do that."
But when it comes down to the decision for an individual patient, Newman stressed that "[i]t is important to address the emotional needs of each breast cancer patient and, as physicians, we should respect a woman's choice for contralateral prophylactic mastectomy."
That is, "as long as the patient is physically fit for the procedure; understands the complications; if she is clear on the fact that her cancer survival rate/treatment needs are driven by the known cancer; and as long as she realizes that she will still require surveillance for developing a new breast cancer or cancer recurrence, despite undergoing the more extensive surgery."
The clinicians who spoke to Medscape for this article have disclosed no relevant financial relationships.
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