The NSABP-32 trial is a randomized, phase III clinical trial to compare sentinel node (SN) resection to conventional axillary dissection in clinically node-negative breast cancer patients. The primary aims of the trial are to determine if removal of only SNs provides survival and regional control equivalent to those of axillary dissection, while diminishing the magnitude of surgically related side effects. In order to ensure consistency of the outcomes for this trial, a standardized method of SN surgery has been utilized for all cases. A secondary aim of the B32 trial is to evaluate whether patients with "occult" metastases in the SNs have worse survival. Accrual is taking place at 73 institutions in North America, and 217 surgeons are enrolling patients.