Dr Vega on an Analysis of Outcomes with Axillary Surgery in Breast Cancer Post-Neoadjuvant Chemo

Raymond Mailhot Vega, MD, MPH, clinical associate professor, Department of Radiation Oncology, University of Florida College of Medicine, discusses the efficacy of axillary surgery in patients with breast cancer previously given neoadjuvant chemotherapy, according to findings from a retrospective analysis.

The analysis compared axillary and breast responses to axillary lymph node dissection (ALND), sentinel lymph node biopsy (SLNB), or a combination of the two, Vega begins. Patient data was compiled from 2 randomized phase 3 trials of neoadjuvant chemotherapy: NSABP B40 (NCT00408408) and B41 (NCT00486668), Vega states. NSABP B40 included patients with HER2-negative disease, while NSABP B41 enrolled those with HER2-positive breast cancer, he details. In both trials, regional nodal irradiation (RNI) and axillary surgery were administered according to the investigator's choice, Vega adds. Efficacy outcomes that were evaluated included locoregional recurrence, distant recurrence, disease free survival, and overall survival (OS).

Results showed that patient outcomes with aggressive axillary surgery were not superior to those with less aggressive axillary surgery, Vega reports. Of the 518 patients from B40 who were lymph node positive, 28% experienced an event after SLNB (n = 7/25) vs 29.5% with ALND (n = 69/234) and 41.3% with the combination (n = 107/259). The percentage of these patients on B41 who experienced an event were 50% (n = 3/6), 34.9% (n = 15/43), and 42.9% (n = 27/63), respectively. Multivariable analysis of the entire cohort showed that treatment with SLNB was not associated with a higher risk of relapse or lower survival vs ALND or ALND plus SLNB (HR >1).

Publication of data from the phase 3 Alliance A011202 study (NCT01901094) will provide more definitive, level 1 guidance regarding the optimal use of axillary surgery vs RNI for this population, Vega emphasizes. The trial is evaluating the efficacy of these modalities in patients with cN1 breast cancer whose tumors downstage to node negative after neoadjuvant chemotherapy but remain pN+.