Axillary Ultrasound After Neoadjuvant Chemotherapy for Node-Positive Breast Cancer Could Reduce Sentinel Lymph Node False-Negative Rate
In the American College of Surgeons Oncology Group Z1071 trial, sentinel lymph node surgery after neoadjuvant chemotherapy was associated with a 12.6% false-negative rate in breast cancer patients with cN1 disease. In an analysis of axillary ultrasound findings in the trial, a secondary endpoint, Boughey and colleagues found that a strategy of performing sentinel lymph node surgery in patients with normal axillary ultrasound findings could reduce the sentinel lymph node false-negative rate. The findings were reported in the Journal of Clinical Oncology.
Study Details
In the trial, patients with T0-4, N1-2, M0 breast cancer underwent axillary ultrasound after neoadjuvant chemotherapy and fine-needle aspiration cytology. Ultrasound images were centrally reviewed and classified as normal or suspicious. Postchemotherapy axillary ultrasound images were reviewed for 611 patients. Among them, 130 (72%) of 181 with axillary ultrasound–suspicious findings were node-positive at surgery compared with 243 (56.5%) of 430 with axillary ultrasound–normal findings (P < .001).
Axillary Ultrasound Findings
Patients with axillary ultrasound–suspicious nodes were likely to have a greater number of positive sentinel lymph nodes (34.5% vs 21.0% with at least two, P < .001), greater nodal disease burden (median sentinel lymph node metastasis of 11.0 vs 6.5 mm, P < .001), additional positive axillary lymph nodes and greater number of additional positive nodes (1–3 in 31% vs 23%, 4–10 in 18% vs 12%, > 10 in 4.4% vs 2.6%; P = .004), and residual invasive disease (pT1 or greater in 75% vs 64%, P = .006).
Sentinel lymph node false-negative rates did not differ based on axillary ultrasound results. However, it was calculated that a strategy of performing sentinel lymph node surgery with resection of at least two sentinel lymph nodes only in patients with normal axillary ultrasound would reduce the false-negative rate from 12.6% to 9.8%.
The investigators concluded: “[Axillary ultrasound] is recommended after chemotherapy to guide axillary surgery. [A false-negative rate] of 9.8% with the combination of [axillary ultrasound] and [sentinel lymph node] surgery would be acceptable for the adoption of [sentinel lymph node] surgery for women with node-positive breast cancer treated with neoadjuvant chemotherapy.”
Judy C. Boughey, MD, of the Mayo Clinic, is the corresponding author of the Journal of Clinical Oncology article.
The study was supported by National Cancer Institute grants. Elizabeth A. Mittendorf, MD, PhD, reported research funding from Galena Biopharma and Antigen Express.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
