Highlights•This study aimed to find the clinical significance of the extracapsular extension in sentinel lymph nodes on the number of additional involved axillary lymph nodes, overall survival, and disease-free survival.•One hundred twenty-eight patients with positive sentinel lymph nodes were separated into two groups according to the presence or absence of ECE and following during 10 years.•There was found a positive correlation between the presence of ECE and the number of additional positive lymph nodes. Therefore, this does not impact overall survival, and disease-free survival in a follow-up of 10 years.