Axilla Management Approach Evolving in Breast Cancer

Laura Kruper, MD, MS

Refinements in surgical techniques and the use of neoadjuvant chemotherapy are leading surgeons away from aggressive management of the axilla with axillary lymph node dissection in women with node-negative and -positive breast cancer, explained Laura Kruper, MD, MS.

Data from the ACOSOG Z0011 trial demonstrated the equivalence of a sentinel node dissection to that of an axillary lymph node dissection in women with lymph node involvement. Six-year follow-up findings showed that the results remain the same, said Kruper—women with T1 or T2 invasive breast cancer and sentinel lymph metastasis who underwent breast-conserving surgery and sentinel node dissection had noninferior outcomes to those randomized to undergo axillary dissection. At a median follow-up of 9.3 years, the 10-year rates of overall survival were 86.3% and 83.6% in the sentinel and axillary dissection arms, respectively (HR 0.85; 1-sided 95% CI, 0-1.16; noninferiority P =.02).

However, the field is still in need of data to address patients who have positive lymph nodes after receiving neoadjuvant chemotherapy, explained Kruper.

“There's more to discern,” she said. “Studies have shown that it's safe to do a sentinel node [dissection] after neoadjuvant chemotherapy in a node-negative woman, but what do you do with the node-positive woman?”

In an interview during the 2019 OncLive^® State of the Science Summit™ on Breast Cancer, Kruper, director, Women’s Center, chief of Breast Surgery Service, associate professor, Division of Surgical Oncology, Department of Surgery, City of Hope, discussed these outstanding questions within the context of the current management of the axilla.

OncLive: How should surgeons approach the management of the axilla?

Kruper: I break down the management of the axilla into 2 components: what to do with the axilla and axillary nodes in a patient who has surgery first versus a patient who has surgery after neoadjuvant chemotherapy. Regarding patients who had surgery first, 2 things have changed our practice.

First, is the ACOSOG Z0011 trial, which was pretty practice-changing. The trial looked at whether women with positive sentinel nodes could be spared an axillary node dissection and just watched. These women were randomized to undergo either a sentinel node dissection or an axillary node dissection. [Current data] solidify that the results have not changed. There is no survival difference or regional recurrence difference between the 2 groups. Women who have a lumpectomy with a sentinel node [dissection] don’t need to have the rest of their lymph nodes removed. That saves a lot of women the risk of lymphedema.

The second change comes with the Society of Surgical Oncology Choosing Wisely guidelines. Each society, not just [breast oncology], was asked to come up with 5 guidelines that would minimize overtreatment, overdiagnosis, and overtesting. One of the guidelines in breast cancer recommends that women over the age of 70 years with hormone receptor (HR)—positive breast cancer should not receive a sentinel node [dissection]. Specifically, surgeons should not even examine the axilla because these women are all going to receive endocrine therapy or antiestrogen therapy as their treatment. These women tend to do well [with that]. Axillary recurrences are very rare, and there are data to support this. Now, I’m doing less sentinel node biopsies in my patients over the age of 70 years with HR-positive breast cancer.

Have there been any advances made in terms of aesthetic outcomes?

Yes. There is a big component of aesthetics or attention to aesthetics [in this space]. I finished my fellowship in 2008. Since then, we have been sparing the nipple more and more in women by keeping the whole envelope of the breast. We can do inframammary incisions, which essentially allows us to hide the scar so that the whole breast maintains its appearance. I mentioned that we're trying to do less axillary surgery to minimize the risk of lymphedema. Some of our plastic surgeons will use prepectoral implants above the muscle so that there's less pain. There is also less animation, which means you can see the muscles when the implants are put under them. We work hand-in-hand with our plastic surgeons all the time. We rely on them heavily. They can do all different types of breast reconstruction. Additionally, many of the breast surgeons have learned how to do oncoplastics, in which we learn how to mobilize areas of the breast to fill in defects so that the breast retains its shape.

Is there more to discover in terms of the optimal management of the axilla?

Yes. If patients achieve a pathologic complete response in the lymph nodes, [we may not do] a full axillary lymph node dissection. However, you need to make sure you can adequately sample the lymph nodes. [In my presentation, I spoke] about targeted axillary dissections or ways to minimize getting a false negative result.

Additionally, we are looking at whether there is going to be a time where we don’t have to [use surgery to treat the lymph nodes]. Additionally, [we’re also trying to determine] whether we’ll be able to diagnose patients whose disease has converted from node-positive to node-negative with chemotherapy, and whether we can do that with liquid biopsies. I might be out of a job in 10 or 20 years, but we'll see. The goal is to try and minimize what we're doing.

Another question revolves around robotic mastectomies. I have not tried it yet, though I'd like to. Part of the difficulty in doing a nipple-sparing mastectomy is trying to dissect out the entire breast and preserve the blood supply to the nipple and skin through a tiny incision. Part of the benefit with robotic surgery is that you can blow up a space and see much better than you would if you were using retractors yourself. That might be the next frontier.

What are some of the ways to minimize false negatives?

Neoadjuvant chemotherapy does such a great job of killing cancer that it can also knock out the lymphatics. If that happens, the blood supply to the lymph node goes away as well as the lymphatic drainage, so it can be hard to do a sentinel node biopsy in a woman who has had chemotherapy. You want to make sure that you're adequately sampling the lymph nodes. That person is at high risk of local regional recurrence if you've missed a lymph node that was resistant to chemotherapy. To reduce the false negative rate, you can put a clip at the time of biopsy in the positive node and make sure you get that clipped node in surgery in addition to doing a standard sentinel node biopsy. You can also use dual tracers, so radioisotope as well as blue dye. Then, [you can harvest] more than 3 lymph nodes. All of those methods combined reduce the false negative rate to a pretty low result.

Giuliano AE, Ballman KV, McCall L, et al. Effect of axillary dissection vs no axillary dissection on 10-year overall survival among women with invasive breast cancer and sentinel node metastasis: the ACOSOG Z0011 (Alliance) randomized clinical trial. JAMA. 2017;318(10):918-926. doi: 10.1001/jama.2017.11470.