Judy C. Boughey, MD
Concerns over false-negative rates with sentinel lymph node biopsies have prevented the widespread adoption of sentinel lymph node surgeries in women with node-positive breast cancer. However, improvements in surgical techniques and the development of neoadjuvant therapies have allowed wider eligibility for the procedure, explained Judy C. Boughey, MD.
“With these techniques, we can drive that false-negative rate lower, enable more of our patients to be candidates for a sentinel lymph node surgery, and potentially avoid the morbidities associated with a complete axillary lymph node dissection,” explained Boughey.
Patients who are eligible for sentinel lymph node surgery show node negativity following neoadjuvant chemotherapy, noted Boughey. Although it may not be the predominant surgical approach, it offers a less invasive treatment approach for select patient populations.
“The dissemination of this possibility for patients has been going relatively well,” added Boughey. “It is a change, and the community oncologists and surgeons need to be comfortable with the data. They need to be aware of all of the tools in the toolbox.”
In an interview during the 2018 OncLive®
State of the Science Summit™ on Breast Cancer, Boughey, chair of the Division of Surgery Research, Mayo Clinic, discussed the surgical management of the axilla in patients with node-positive breast cancer and less invasive approaches for disease management.
OncLive: What are the new techniques in the surgical management of women with node-positive breast cancer?
: Women who have node-positive breast cancer are often treated with neoadjuvant chemotherapy. When patients have involvement in the lymph nodes at their initial presentation, the standard, up until several years ago, was to resect all lymph nodes with an axillary lymph node dissection.
Several prospective trials conducted in America, Canada, and Europe have looked at whether we can avoid doing a full axillary dissection and identify the patients in which neoadjuvant chemotherapy has effectively transitioned the lymph nodes from being positive to negative. This allows those patients to have a few lymph nodes removed with what's called a sentinel lymph node surgery; that way, we can limit the use of axillary lymph node dissection to those women who still have disease in their lymph nodes after neoadjuvant chemotherapy.
All 3 of those prospective trials showed a false-negative rate. There was an error rate around about 10% to 14%, depending on the trial. Since those trials have been published, there have been several improvements in technique that are driving down the false-negative rate and making the procedure as safe as possible for patients.
Examples of those techniques include making sure the surgeon uses a dual tracer—which is usually a radioactive colloid—and a blue dye, as that increases the identification rate of the sentinel node and decreases the false-negative rate associated with sentinel lymph node surgery. Another technique is using a clip that can be placed by the surgeon. Prior to chemotherapy, at the time of the needle biopsy, [the clip is placed] in the positive lymph node. Then, when the sentinel lymph node surgery is performed, [surgeons will] remove the clip node.
A third technique that is being widely adopted is the use of immunohistochemistry. We’re encouraging our pathologists to look a little bit closer at the sentinel lymph node to identify what might be just small volumes of disease, isolated tumor cells, or foci of disease that are less than 1 mm or even less than 0.2 mm in size. Then, [pathologists should] consider those patients as node-positive and proceed with an axillary lymph node dissection.
What are the recommended neoadjuvant therapies for women with node-positive breast cancer?
The neoadjuvant therapies for patients with node-positive breast cancer are continually evolving. In the past, the conversion rate in women who [went from] node-positive to node-negative when treated with neoadjuvant chemotherapy was 20% or 30%. Now, we're seeing conversion rates ranging from 50% to 60%, or even higher. Specifically, patients with HER2-positive breast cancer who receive chemotherapy with dual HER2-targeted therapy are showing conversion rates as high as 65% to 70%.
What is the benefit of surgical management of the axilla for patients?
If a patient had gone to the operating room when they were first diagnosed, the standard recommendation would have been an axillary lymph node dissection. Delivering the chemotherapy in the neoadjuvant setting gives that patient the benefit of seeing [an antitumor response] and a chance to consider less invasive surgery after completing chemotherapy.