Is Preoperative Axillary Imaging Beneficial in Identifying Clinically Node-Negative Patients Requiring Axillary Lymph Node Dissection?

Abstract

Background: American College of Surgeons Oncology Group (ACOSOG) Z0011 results support the omission of axillary lymph node dissection (ALND) in women with less than 3 positive sentinel lymph nodes (SLNs) undergoing breast-conserving surgery (BCS) and radiation therapy. We sought to determine if abnormal axillary imaging is predictive of the need for ALND in this population.

Study design: Patients with cT1-2N0 breast cancer by physical examination undergoing BCS were managed according to Z0011 criteria independent of axillary imaging. Patient characteristics and rates of ALND were compared among those with and without abnormal lymph nodes (LNs) detected by mammogram, ultrasound (US), or MRI. All available axillary imaging was reviewed by 1 breast radiologist.

Results: Between August 2010 and December 2013, 3,253 breast cancer patients were treated with BCS and SLN biopsy; 425 patients met Z0011 criteria (cT1-2N0) and had nodal metastasis on SLN biopsy. Clinicopathologic features were median patient age, 58 years; median tumor size, 1.8 cm; 85% ductal histology; and 89% estrogen receptor positive. All women had a mammogram, 242 had axillary US, 172 had MRI. Abnormal LNs were seen on 7%, 25%, and 30% of mammograms, US, and MRIs, respectively. Although abnormal LNs on mammogram or US were associated with a significant increase in ALND and a non-significant trend was seen with MRI, 68% to 73% of women with abnormal axillary imaging did not require ALND.

Conclusions: Among clinically node-negative patients with abnormal axillary imaging, 71% did not meet criteria for ALND and were spared further surgical morbidity. Abnormal nodes on US, MRI, or mammogram in clinically node-negative patients are not reliable indicators of the need for ALND.