More Younger Women Opting for Bilateral Mastectomy

Liam Davenport

December 11, 2017

SAN ANTONIO ---- Younger women with operable breast cancer are increasingly likely to choose bilateral mastectomy with immediate reconstruction rather than breast-conserving surgery, regardless of their response to neoadjuvant chemotherapy, a US study shows.

In an analysis of data on more than 230,000 women, Erqi L. Pollom, MD, MS, Department of Radiation Oncology, Stanford University, California, and colleagues found that rates of bilateral mastectomy increased significantly between 2010 and 2014, while those of unilateral mastectomy decreased.

The choice of mastectomy, as opposed to breast-conserving surgery, was associated with younger age, non-Hispanic white race, and living farther from the treatment facility and in more educated areas, as well having a more advanced clinical stage and having private/managed health insurance.

"Further study of non-clinical factors that influence surgical decision-making in the neoadjuvant chemotherapy setting is warranted," the team says in a poster presented here at the San Antonio Breast Cancer Symposium (SABCS) 2017.

To examine surgical trends in operable breast cancer, the researchers examined data from the National Cancer Database on women diagnosed with unilateral T1-3N0-3M0 breast cancers between 2010 and 2014 and treated with surgery and chemotherapy.

They identified 235,339 women who met the inclusion criteria, of whom 59,568 (25.3%) were treated with neoadjuvant chemotherapy.

Between 2010 and 2014, the rate of pathologic complete response to neoadjuvant chemotherapy increased significantly, from 33.3% to 46.3% (P = .02).

The team found that rates of breast-conserving surgery remained stable over the study period, changing from 37.0% to 40.8% between 2010 and 2014 (P = .22). Similarly, rates of bilateral mastectomy without immediate reconstruction were unchanged, at 11.7% and 11.5%, respectively (P = .82).

In contrast, rates of unilateral mastectomy decreased significantly between 2010 and 2014, falling from 43.3% to 34.7% (P = .02), while rates of bilateral mastectomy with immediate reconstruction rose from 8.0% to 13.2% (P = .02).

Logistic regression analysis showed that, irrespective of receipt of neoadjuvant chemotherapy and pathologic complete response status, three groups of women were more likely to undergo unilateral and bilateral mastectomy than breast-conserving surgery. The groups were those who were younger than age 40 years, lived more than 50 miles from their medical facility, and had a higher clinical stage.

Black race and distal histology were both inversely associated with unilateral and bilateral mastectomy, while more recent year of diagnosis was inversely associated with unilateral mastectomy and directly associated with bilateral mastectomy.

Bilateral mastectomy was also associated with private or managed care insurance and higher education, the team says, noting that the results were unaffected by sensitivity analyses.

In-depth Thoughts About These Trends

Judy C. Boughey, MD, professor of surgery and a surgical oncologist at the Mayo Clinic, Rochester, Minnesota, who was not involved in the study, told Medscape Medical News that several studies have looked at surgical trends in breast cancer.

Dr Judy C. Boughey

"It seems like we have a paper a week coming out, showing pretty similar trends: that nationally the rates of mastectomy and the rates of bilateral mastectomy seem to be going up," she said.

Dr Boughey explained that in making the final decision regarding surgical management, "it often comes down to the discussion of lumpectomy vs mastectomy, [and] for many patients you can see that they're basically only weighing up the breast-conserving approach vs bilateral mastectomy."

She said that many women are choosing the bilateral approach "from the standpoint of, in their mind, minimizing their risk of future breast cancer."

Dr Boughey pointed out that "we know from a data standpoint that removing the contralateral breast does not improve their survival" but that the decision can be more of a psychological one, taking into account the decreased need for mammography in the other breast and the symmetry of having both breasts removed and reconstructed.

She noted that women who receive adjuvant chemotherapy, by definition, "have a longer time between diagnosis and making that final surgery choice, so they potentially go on more chat rooms or meet more people in the chemotherapy unit and talk about their experiences. It's not uncommon that when I see patients after chemotherapy they say, 'I just don't ever want to go through chemotherapy again.'"

"To them, it's taking the most radical route, removing both breasts, trying to maintain as much control over this disease they can."

Dr Boughey said she points out that the other breast is not the source of the highest risk for subsequent breast cancer because there is a greater risk for a local or distant recurrence of the tumor they are being treated for, "but, from the woman's standpoint, they often want to go with the bilateral mastectomy."

She emphasized that the choice is personal but should come down to what the woman will be comfortable with in 5 or 10 years, rather than in the next 1 or 2 months.

"It's thinking about how they feel in the shower and in the bedroom, 3 to 5 years after," she said.

In terms of the factors associated with mastectomy vs breast-conserving surgery, Dr Boughey said that the sample size was so large that "pretty much any analysis" is going to give significant results.

She said that the factors associated with bilateral mastectomy were in line with those identified in previous studies and were "not particularly surprising."

Dr Boughey highlighted an analysis she led that looked at data from ACOSOG Z1071, a prospective, multicenter study that assessed rates of breast-conserving surgery and pathologic complete response after neoadjuvant chemotherapy in 765 patients with node-positive breast cancer.

This showed that women who had triple-negative breast cancer and those with human epidermal growth factor receptor 2 (HER2)–positive tumors were significantly more likely to choose breast-conserving surgery than those with hormone receptor–positive, HER2-negative tumors (P = .019).

Dr Boughey pointed out that this is to be expected because those are the women who have the highest rates of pathologic complete response.

"One of the challenges in this area is, when you give neoadjuvant chemotherapy, you're hoping that they're going to have an excellent response, you're hoping that the chemotherapy is going to eradicate the tumor from the breast," she said.

While 10 years ago, neoadjuvant chemotherapy was given to help with breast-conserving surgery, "now we give it more based on tumor biology, in terms of identifying response to chemotherapy; so we give it not based on their surgical preference," Dr Boughey continued.

"But it is somewhat disappointing when you see patients who have a great response who could save their breast, and then are not interested in saving their breast."

No funding was reported. The investigators have disclosed no relevant financial relationships .

San Antonio Breast Cancer Symposium (SABCS) 2017. Poster P6-08-04. Presented December 9, 2017.

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