Second echelon node predicts metastatic involvement of additional axillary nodes following sentinel node biopsy in early breast cancer

BACKGROUND : In many patients with early breast cancer, the sentinel lymph node (SLN) is the sole site of regional nodal metastasis. This subgroup of patients may not benefit from completion axillary lymph node dissection (CALND).
AIMS: This pilot study evaluates the status of 2nd echelon (station) lymph nodes in the axilla as a predictor of additional positive nodes in the axilla in the presence of sentinel node metastasis. SETTINGS AND DESIGN: Cross-sectional study of 40 breast cancer patients.
MATERIALS AND METHODS: Forty patients with invasive breast cancer underwent SLN biopsy followed by 2nd echelon lymph node biopsy in the same sitting. SLN mapping was performed using a combined technique of isosulfan blue and 99 mTc-sulfur colloid. SLNs (Station I) were defined as blue and/or hot nodes. These nodes were then injected with 0.1 ml of blue dye using a fine needle and their efferent lymphatic was traced to identify the Station II nodes. Then a complete ALND was performed. All the specimens were sent separately for histopathological evaluation.
RESULTS : SLNs (Station I nodes) were successfully identified in 98% (39/40) patients. Of the 17 patients with a positive SLN, 8 (47%) patients had no further positive nodes in the axilla, 9 (53%) patients had additional metastasis in nonsentinel lymph nodes upon CALND. Station II nodes were identified in 76% (13/17) patients with a positive SLN. Station II nodes accurately predicted the status of the remaining axilla in 92% patients (12/13).
STATISTICAL ANALYSIS : We calculated the Sensitivity, Negative predictive value, Positive predictive value, False negative rate and Identification rate.
CONCLUSION : Station II nodes may predict metastatic involvement of additional nodes in the axilla.

Keywords
Axillary lymph node dissection, breast cancer, sentinel node (station I node), second echelon (station) node