If a woman didn’t need one breast removed to treat her breast cancer, it would seem unlikely that she’d opt to have both breasts removed.
Yet, despite the fact that contralateral prophylactic mastectomy (CPM) does not improve overall survival for women with average-risk of getting breast cancer, use of the procedure persists. And for small tumors, unilateral mastectomy may be unnecessary too. When coupled with radiation and sometimes hormone therapy, breast-conserving surgery (BCS), usually lumpectomy, often effectively treats the cancer.
Such overtreatment was the target of a paper in the Journal of Surgical Research by co-first authors Alison Baskin, a University of Michigan medical student, and Ton Wang, M.D., a University of Michigan General Surgery Resident. Lesly Dossett, M.D., M.P.H., was the paper’s primary investigator.
“The motivation for all of this is that while there may be some value to the patient, like peace of mind and cosmetics, there’s a growing body of literature documenting the harms of this extensive surgery,” Dossett says.
Getting at the “why” of low value care
Through the Choosing Wisely campaign, which aims to reduce low value health care, prominent surgical societies have targeted procedures that confer little or no benefit as a way to reduce overtreatment and minimize potential harm to patients.
Among these recommendations is the elimination of CPM for average-risk women with unilateral cancer. A previous paper by a team including Dossett and Wang examined the variations in reducing the low-value breast cancer procedures, like CPM, which have been targeted by the Choosing Wisely campaign.
The CPM study was designed to evaluate variables that may influence breast cancer treatment decisions. It focused on a population of women from the National Cancer Database: 765,487 women with small, unilateral T1 breast cancer, and then more specifically 176,673 women who were older than 70 years with hormone receptor-positive (HR+) cancer.
Study participants had disease characteristics for which guidelines recommend omission of not only CPM, but also unilateral mastectomy. These women should instead receive BCS. The ≥70 years group could also, per current guidelines, omit post-surgical radiation—which is normally required after lumpectomy but not mastectomy and therefore leads some women to pursue mastectomy despite a small tumor size. The domino effect continues: Once women have a unilateral mastectomy, they may be more likely to undergo a bilateral mastectomy (CPM). Taken altogether, this suggests that decisions to pursue CPM are likely influenced by reasons other than current treatment guidelines.
“This study was unique and interesting to us because it targeted a very specific patient population where a lot of these treatment recommendations seem to align. We could study a specific question and account for variables like not needing post-surgical radiation, the tumor size being small, these women having a likely favorable prognosis but where these unnecessary treatments might be particularly harmful,” Baskin says.
What the data showed
Of the women in the larger cohort, 69% underwent BCS, 22% had a unilateral mastectomy and 9% underwent CPM. Of the women older than 70, 75% underwent BCS, 22% chose unilateral mastectomy, and 3% underwent CPM.
The team also evaluated for factors associated with CPM utilization—patient demographics, tumor type and treatment facility location. Trends emerged that could help guide conversations with patients.
“Ideally, you could target the patients who may be at greater risk for pursuing CPM based on those factors,” Baskin says.
Women who were young, white or had private insurance in the study were more likely to have received CPM as compared to unilateral mastectomy.
Younger women tended to pursue CPM at a higher rate than unilateral mastectomy if their tumors had certain characteristics: higher grade, lobular histology versus ductal histology, ER negative hormone receptor status versus ER positive, and HER2 receptor positive status versus HER2 negative. The older women in the high CPM utilization group tended to have tumors that were smaller and had lobular histology.
There was a strong link between women receiving breast reconstruction and undergoing CPM, with 29% of unilateral mastectomy patients receiving breast reconstruction compared with 38% of CPM patients.
Where care was received also mattered. Comprehensive community and integrated network cancer programs were more likely to be associated with women receiving CPM; this could be due to such centers offering not just cancer treatment but also more breast reconstruction. Women receiving care at hospitals in New England, the Mid-Atlantic, and East North Central regions had significantly lower odds of receiving CPM than women treated elsewhere.
An escalation pattern, and an opportunity to intervene
While guidelines attempt to nudge women away from more invasive surgery, CPM rates for both cohorts have increased since 2006. Meanwhile unilateral mastectomy has decreased and rates of BCS have remained stable, the study states.
“The rate of CPM utilization was about 9%. That doesn't seem like a big number but when you recognize how many women are diagnosed with breast cancer every year the repercussions are large,” Baskin says.
The repercussions include longer time out of work, higher unemployment rates, financial toxicity and even long-term pain from unnecessary surgery.
The trend toward increased CPM use represents an escalation in care with opportunities to intervene—especially as it pertains to mastectomy and overtreatment.
Dossett notes that once a patient needs a mastectomy to treat their breast cancer, there’s strong momentum toward a medically unnecessary bilateral mastectomy. Despite the lack of survival value, the patients find value: They may want to pursue breast reconstruction, or not worry about having to screen the remaining breast for cancer.
Women who don’t need a mastectomy in the first place could avoid that escalation.
“Can we help reduce the use of CPM by reducing the use of mastectomy in general?” Dossett says.
That may mean longer conversations with patients, providing more tailored information and even debunking things that patients have picked up in the news or on social media. More information isn’t always better information.
“So often patients come to the meeting already having some idea of what they want, probably more so than a patient who presents with colorectal cancer. Sometimes we lack the skill or the time to maybe talk somebody out of something,” Dossett says.
There’s also an opportunity to better educate women about radiation: Older women with low-risk cancer can omit it, and those who can't won’t necessarily suffer the ill effects from it that they think they will.
“Sometimes people are confused about the side effects. They might know somebody who had chemotherapy and lost their hair or had a lot of nausea and vomiting and think that’s going to happen with radiation. That’s not true,” Dossett says.
In one bright spot, the study noted a decrease in radiation in older women correlated with increased BCS rates. That may demonstrate that improved information sharing is already having some effect.
Baskin, who plans to pursue surgery as a speciality, is interested in knowing more about how those conversations are going.
“Patients have identified a desire to achieve peace of mind as a key factor for pursuing CPM. At the same time, patients put a lot of trust in their providers when making treatment decisions. I’d be interested in understanding more about what conversations between patients and surgeons take place in clinic and I’d be curious to ask these women what information they’re coming across,” Baskin says.
By Colleen Stone