Is axillary lymph node dissection necessary after sentinel lymph node biopsy in patients with mastectomy and pathological N1 breast cancer?

BACKGROUND: The American College of Surgeons Oncology Group (ACOSOG) Z0011 trial reported that axillary lymph node dissection (ALND) did not change the recurrence and overall survival (OS) rates in patients with lumpectomy and one to two positive nodes detected by sentinel lymph node biopsy (SLNB). The aim of this study was to determine whether patients with mastectomy and pathological N1 disease found by SLNB could forego ALND. MATERIALS AND METHODS: This is a retrospective study of 214 patients diagnosed with primary invasive breast cancer who were treated by mastectomy and lymph node staging surgery (SLNB or ALND) at the Revlon/UCLA Breast Center between January 2002 and December 2010. Patients with pathological N1 disease were separated by their first nodal surgery into SLNB (subgroups: observation, radiation, and additional ALND with or without radiation) and ALND groups (subgroups: ALND with or without radiation). RESULTS: After a median follow-up of 43.6 months, the OS and systemic relapse-free survival (RFS) rate of the radiation group and additional ALND group were significantly better than the observation group (p = 0.031 and 0.046, respectively). Human epidermal growth factor receptor 2 (HER2) expression was found to predict OS and patients' age, histological grade and HER2 expression predicted systemic recurrence. Compared with the SLNB group, pain (p = 0.021) and lymphedema (p = 0.043) occurred more frequently in the ALND group. CONCLUSION: Radiation was as effective as ALND in patients with mastectomy and N1 disease for OS and RFS rates, yet radiation after SLNB had fewer side effects than ALND. SLNB followed by radiation could replace ALND in patients with mastectomy and pathological N1 breast cancer identified by SLNB.