Breast Cancer Chemo Responders May Avoid Lymph Node Surgery

BARCELONA, Spain — Lymph node surgery to check for the spread of breast cancer could be avoided even in women with aggressive cancers if they respond well to initial chemotherapy, suggest the results of two new studies.

The findings, presented at the 11th European Breast Cancer Conference, suggest that some women with triple-negative or HER2+ disease could therefore avoid axillary surgery and its associated adverse affects.

"Whether or not a breast cancer has spread to nearby lymph nodes is a key indicator of a patient's prognosis," commented Robert Mansel, MD, chair of the conference and professor emeritus of surgery at Cardiff University School of Medicine, United Kingdom.

"That's why sentinel lymph node biopsy has been an important part of treating breast cancer," he continued.

However, the procedure is associated with ongoing adverse effects in some women, such as swelling, numbness, and reduced movement of the arm

"These two studies give us clues on which patients have a very low risk of cancer in their lymph nodes after chemotherapy. This could enable us to reduce unnecessary surgery when it's safe to do so, helping us tailor treatments towards individual patients," Mansel commented in a statement.

Finding No Cancer Cells in Lymph Nodes

One of the new studies was presented at the meeting by Christian Sisó, MD, University Hospital Vall Hebron, Barcelona, Spain. To determine whether axillary surgery can be avoided in cN0 breast cancer patients, Sisó and colleagues studied 90 women with either HER2+ or triple-negative breast cancer who underwent neoadjuvant treatment between 2011 and 2016.

All the women underwent axillary ultrasound, the findings of which were confirmed on cytologic testing.

The team found that, prior to treatment, 54 (60%) of the women had cN0 disease; the remaining 36 (40%) had N1 disease.

Among the patients with cN0 disease, 23 patients (42.5%) had a pathologic complete response in the breast following neoadjuvant treatment; 52 (96.3%) showed no evidence of metastases in the axillary lymph nodes.

Of the two patients (3.7%) with residual axillary disease, none achieved a pathologic complete response in the breast.

Among the patients with N1 disease, 17 had a pathologic complete response in the breast to neoadjuvant therapy. For 13 (76.5%) of those patients, there was no evidence of residual disease in the axillary nodes.

This was significantly more than the seven (36.8%) patients without residual axillary disease among those without a pathologic complete response (P = .02).

The team found that women with a pathologic complete response in the breast were less likely to test positive for nodal metastases than women without a pathologic complete response, at a relative risk of 0.35.

Sisó said: "In women who had no signs of cancer in their lymph nodes and where treatment seems to have cleared the cancer in the breast, lymph node surgery might be avoided.

"On the other hand, in women who had signs of cancer in their lymph nodes before treatment, there is still a risk that the disease will remain there, even when it has been successfully treated in the breast itself.

"Our results suggest that giving chemotherapy to patients with these types of breast cancer before considering surgery offers the possibility of reducing, or even avoiding, surgery," Sisó said in a statment.

Patients Least Likely to Have Axial Disease

In the other study, Marieke van der Noordaa, MD, from the Netherlands Cancer Institute–Antoni van Leeuwenhoek Hospital, Amsterdam, studied 298 cN0 breast cancer patients at their institute between 2013 and 2017. They were looking for factors that were predictive of disease-negative sentinel lymph nodes after neoadjuvant therapy.

The team found that 258 (86.6%) of the women had tumor-negative sentinel lymph nodes, 16 (5.4%) had macrometastasis, 16 (5.4%) had micrometastasis, and eight (2.7%) had isolated tumor cells.

There was a significant difference in the proportion of patients with negative sentinel lymph node findings with respect to tumor subtypes. Among patients with hormone receptor–positive (HR+), HER2+ disease, sentinel lymph node findings were negative for 78%; for patients with HER2+/HR- disease, the findings were negative for 100%; and for women with triple-negative tumors, the findings were negative for 98.5% (P < .001).

Women who had a good response to chemotherapy were more likely to have negative lymph nodes, they reported.

Among the women who had a radiologic compete response in the breast, 95.2% had negative lymph nodes, compared with 79.3% who did not (P < .001). Among the women who had a pathologic complete response, 100% had negative lymph nodes, compared with 92.5% who did not (P < .001).

On multivariate analysis, the investigators found that the only factor that was a significant predictor for having negative sentinel lymph nodes was a pathologic compete response.

"These results suggest that sentinel lymph node biopsies are most likely not needed in many women who undergo up-front chemotherapy and who have no sign of cancer in their lymph nodes before the start of chemotherapy," van der Noordaa commented.

The investigators have disclosed no relevant financial relationships.

European Breast Cancer Conference (EBCC-11). Abstracts 20 and 104, presented March 22, 2018.

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