Preoperative predictors of high and low axillary nodal burden in Z0011 eligible breast cancer patients with a positive lymph node needle biopsy result.

BACKGROUND: Z0011 trial showed that early breast cancer patients with low axillary nodal burden, may be spared an axillary lymph node dissection with no survival compromise. Axillary lymph node dissection can be reserved for patients with a high axillary nodal burden. We aim to determine the preoperative factors that could distinguish between low and high axillary nodal burden in Z0011 eligible patients with a needle biopsy proven metastatic node.

METHOD: Patients who fulfilled Z0011 trial criteria with a positive lymph node needle biopsy and had axillary lymph node dissection (ALND) were recruited. These patients were classified into low and high nodal burden subgroups, defined as having 1-2 and ≥3 metastatic lymph nodes, respectively. The clinical, radiological and pathological features between the 2 subgroups were compared.

RESULTS: 70 (40%) and 105 (60%) patients had low and high nodal burden respectively. The high nodal burden subgroup was more likely to have on ultrasound ≥3 abnormal lymph nodes (37.14% versus 4.29%) (P < 0.0001) and maximum cortical thickness >4 mm (31.43% versus 10.0%) (P = 0.0036). Multivariate analysis revealed abnormal lymph nodes ≥3 to have an odds ratio of 20.72 (95% CI 5.91-72.65) P < 0.0001.

CONCLUSION: ≥3 abnormal lymph nodes on ultrasound was the most significant predictor of high nodal burden subgroup in Z0011 eligible patients with a positive lymph node needle biopsy. This information could allow this subgroup to proceed to an upfront ALND and avoid the need of a sentinel lymph node biopsy in the post Z0011 trial era.