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

Abstract

101 Background: Recently, axillary lymph node dissection (ALND) was shown to be unnecessary in patients with lumpectomy and 1-2 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. Methods: 214 patients with primary invasive breast cancer who were treated by mastectomy and lymph node staging surgery (SLNB or ALND) at UCLA were identified between Jan. 2002 and Dec. 2010. Patients were grouped 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, in the SLNB group, the 5-year OS rate was worse in the observation group (71%) when compared to 94% in the additional ALND group and 100% in the radiation group (p=0.031). Systemic recurrence rate in patients with positive SLNs was also significantly higher in the observation group (17.4%) when compared with 7.8% in the additional ALND and no recurrence in the radiation group (p=0.046). Her-2 expression (p=0.006, HR 7.493, 95%CI 1.781~31.520) was found to predict OS. Young age (p=0.024, HR 0.921, 95%CI 0.857~0.989), higher histological grades (p=0.021, HR 5.571, 95%CI 1.295~23.954), and positive Her-2 status (p=0.013, HR 8.916, 95%CI 1.590~49.995) were significant in predicting systemic recurrence in the multivariate analysis with type of nodal surgery and radiation controlled. Compared to the SLNB group, pain (p=0.021) and lymphedema (p=0.043) occurred more frequently in the ALND group. Conclusions: Radiation was as effective as complete ALND in patients with mastectomy and N1 disease detected by SLNB for OS and relapse free survival 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.