ACOSOG Z0011: A randomized trial of axillary node dissection in women with clinical T1-2 N0 M0 breast cancer who have a positive sentinel node.

Abstract

CRA506 Background: Sentinel node biopsy (SNB) eliminates the need for axillary dissection (ALND) in patients whose sentinel node (SN) is tumor-free. However, completion ALND remains the gold standard for patients with a tumor-involved sentinel node. ALND achieves regional control, but its effect on survival remains controversial. The main objective of ACOSOG Z0011 was to compare outcomes of patients with hematoxylin and eosin (H&E) detected metastasis in SN managed with or without ALND and no axillary irradiation. Methods: Clinically node-negative patients who underwent SN biopsy and had 1 or 2 SN with metastases detected by H&E were randomized to ALND or no further axillary specific treatment. All patients were treated with lumpectomy and opposing tangential field irradiation. Adjuvant systemic therapy was at the discretion of their physicians. Overall survival (OS), disease-free survival (DFS), and locoregional control were evaluated. Results: 446 patients were randomized to SNB alone and 445 to SNB plus ALND. Patients treated with SNB alone were similar to those treated with SNB + ALND with respect to age, tumor size, Bloom-Richardson score, estrogen receptor status, adjuvant systemic therapy, tumor type, and T stage. Patients randomized to SNB alone had a median of two lymph nodes removed whereas patients randomized to ALND had a median of 17 lymph nodes removed. 17.6% of ALND patients had 3 or more involved nodes compared to 5.0% of SNB patients (p < 0.001). Median follow-up is 6.2 years. 5-year in breast recurrence after ALND was 3.7% compared to 2.1% for SNB (p = 0.16) while 5-year nodal recurrence was 0.6% compared to 1.3% (p = 0.44) respectively. The five-year OS for patients undergoing SNB + ALND is 91.9% compared to 92.5% for SNB alone (p = 0.24), and DFS is 82.2% compared to 83.8% respectively (p = 0.13). Conclusions: Despite the widely held belief that ALND improves survival, no significant difference was recognized by this study of SN node-positive women. Although the study closed early because of low accrual/event rate, it is the largest phase III study of ALND for node-positive women, and it demonstrates no trend toward clinical benefit of ALND for patients with limited nodal disease. [Table: see text]