Measurement of extracapsular extension in sentinel lymph node as a possible predictor of residual axillary disease in breast cancer

BACKGROUND: The presence of Extracapsular Extension (ECE) in the Sentinel Lymph Node Biopsy (SLNB) is still a doubt in the literature. Some studies suggest that the presence of ECE may be related to a greater number of positive axillary lymph nodes which could impact Disease Free Survival (DFS) and Overall Survival (OS). This study searches for the clinical significance of the ECE. METHODS: Retrospective cohort comparing the presence or absence of ECE in T1-2 invasive breast cancer with positive SLNB. All cases treated surgically at the Cancer Institute of the State of São Paulo (ICESP) between 2009 and 2013 were analyzed. All patients with axillary disease in SLNB underwent AD. OUTCOMES: Identify the association between the presence and length of ECE and additional axillary positive lymph nodes, OS and DFS between both groups. RESULTS: 128 patients with positive SLNB were included, and 65 had ECE. The mean metastasis size of 0.62 (SD = 0.59) mm at SLNB was related to the presence of ECE (p < 0.008). The presence of ECE was related to a higher mean of positive sentinel lymph nodes, 3.9 (± 4.8) vs. 2.0 (± 2.1), p = 0.001. The median length of follow-up was 115 months. The OS and DFS rates had no differences between the groups. CONCLUSION: The presence of ECE was associated with additional positive axillary lymph nodes in this study. Therefore, the OS and DFS were similar in both groups after 10 years of follow-up. It is necessary for additional studies to define the importance of AD when SLNB with ECE.