Rodrigo Arrangoiz MS, MD, FACS, FSSO

The ACOSOG Z1071 trial:
- Was designed to determine the false negative rate (FNR) of sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) in women initially presenting with cN1 disease
The trial enrolled women from 136 institutions who had clinical T0 through T4, N1 through N2, M0 breast cancer who received neoadjuvant chemotherapy
Patients enrolled had pre-chemotherapy axillary nodal disease confirmed by fine-needle aspiration or core needle biopsy
Following NAC, patients underwent both SLNB, followed by a back-up axillary lymph node dissection
SLNB with dual tracer using both blue dye (isosulfan blue or methylene blue) and a radiolabeled colloid mapping agent was encouraged
Rates of detection of at least one SLN were:
- 92.9% in patients with cN1 disease and 89.5% in patients with cN2 disease
Overall, the FNR of SLNB after NAC was 12.6%
Bivariable analyses found that the likelihood of a false-negative SLN finding was significantly decreased:
- When the mapping was performed with the combination of blue dye and radiolabeled colloid (P=.05; FNR, 10.8% combination vs 20.3% single agent) and by removal of at least 3 SLNs (P=.007; FNR, 9.1% for ≥3 SLNs vs 21.1% for 2):
  - A clip was placed at initial node biopsy prior to NAC in 203 patients:
    - In the 170 (83.7%) patients with cN1 disease and at least 2 SLNs resected, clip location was confirmed in 141 cases
    - In 107 (75.9%) patients where the clipped node was within the SLN specimen;
      - The FNR was 6.8% (confidence interval [CI]: 1.9%-16.5%)
  - If the clipped node was found in the ALND specimen:
    - The FNR was 19.0% (CI: 5.4%-41.9%)
  - In cases where a clip was not placed (n = 355) and in those where the clipped node location was not confirmed at surgery (n = 29):
    - The FNR was 13.4% and 14.3%, respectively
While the FNR overall exceeded the 10% threshold considered to be clinically acceptable, the authors concluded that with modifications to the SLN technique (i.e., dual tracer mapping and retrieval of at least 3 negative SLNs):
- To the FNR was less than 10% and supported the use of SLN surgery as an alternative to axillary lymph node dissection in this patient population
Subsequently, Caudle et al have reported a separate registry of 191 patients and showed that removing the clipped positive node in addition to SLN had an FNR as low as 2.0%
References
- Boughey JC, Suman VJ, Mittendorf EA, Ahrendt GM, Wilke LG, Taback B, et al.; Alliance for Clinical Trials in Oncology. Sentinel lymph node surgery after neoadjuvant chemotherapy in patients with node-positive breast cancer: the ACOSOG Z1071 (Alliance) clinical trial. JAMA. 2013;310(14):1455-1461.
- Boughey JC, Ballman KV, Le-Petross HT, McCall LM, Mittendorf EA, Ahrendt GM, et al. Identification and resection of clipped node decreases the false-negative rate of sentinel lymph node surgery in patients presenting with node-positive breast cancer (T0-T4, N1-N2) who receive neoadjuvant chemotherapy: results from ACOSOG Z1071 (Alliance). Ann Surg. 2016;263(4):802-807.
- Caudle AS, Yang WT, Krishnamurthy S, Mittendorf EA, Black DM, Gilcrease MZ, et al. Improved axillary evaluation following neoadjuvant therapy for patients with node-positive breast cancer using selective evaluation of clipped nodes: implementation of targeted axillary dissection. J Clin Oncol. 2016;34(10):1072-1078.