Predictive Factors for Non-Sentinel Lymph Node Metastasis in Patients with ACOSOG Z0011 Criteria

Nodal staging constitutes an element of great importance in the treatment planning for early breast cancer. The ACOSOG Z0011 trial demonstrated that sentinel lymph node (SLN) biopsy alone results in rates of local control, disease-free survival, and overall survival equivalent to those seen after axillary lymph node dissection. The purpose of this study was to determine the rate of patients that fulfill the ACOSOG Z0011 inclusion criteria and to define predictive factors for non-SLN positivity.

A retrospective analysis of the breast surgery database of the Argentinian Society of Mastology was carried out. Patients were selected if they fulfilled the ACOSOG Z0011 inclusion criteria. The association of clinical and pathological factors with non-SLN positivity was evaluated in univariate and multivariate analysis.

Among 8,262 patients, 973 had positive SLN, and 348 satisfied the inclusion criteria. Histological grade (G3 vs. G1-2, odds ratio (OR) 1.81; p = 0.024), tumor size (T2 vs. T1, OR 2.39; p = 0.001), and age (>50 vs. <50 years, OR 1.95; p = 0.007) were associated with non-SLN positivity in multivariate analysis.

Although the clinical relevance of our data is not established, older women with tumors bigger than 2 cm and/or high histological grade are at greater risk of having metastatic disease in the lymph nodes if axillary lymph node dissection is avoided. This subgroup of patients represents only 30% of the trial population.