All participants were women at least 18 years of age with clinical T1 or T2 N0 M0 breast cancer treated with SLND and breast-conserving therapy as previously described.9 (link) Lumpectomy margins were required to be negative for study participation. Planned mastectomy was not permitted. Patients must have undergone SLND within 60 days of the diagnosis of invasive breast carcinoma and have an ECOG/Zubrod status less than or equal to 2. A SN containing metastatic breast cancer must have been identified by frozen section, touch preparation or permanent section. Patients with metastatic breast cancer to the SN identified by immunohistochemical staining (IHC) were not eligible. Patients were randomized to completion ALND or no ALND and no further axillary-specific therapy, specifically no third field nodal irradiation. All patients received opposing tangential field whole breast irradiation. ALND was defined as an anatomic Level I and II dissection with at least 10 nodes removed. Adjuvant systemic therapy was determined by physician and patient selection. For patients randomized to completion ALND, the operation must have been performed within 42 days of the SLND. Pregnant or lactating patients were excluded as were patients treated with neoadjuvant chemo- or hormonal therapy. In addition, patients with bilateral breast cancer were excluded as were those with multicentric disease, a history of ipsilateral axillary surgery, pre-pectoral implants, or those with medical contraindications to ALND. Patients with matted nodes or gross extranodal disease at the time of SLND were excluded as were patients with three or more involved SNs.
Participants entered the study through two pathways, the most common of which was randomization post-SLND when the final histopathologic results of examination of the SN were known. However, some patients were pre-registered before SLND and then randomly assigned to a treatment arm intraoperatively by an interactive automated telephone system when frozen section or touch preparation analysis documented a tumor-involved SN. Although some of these patients were subsequently found to have three or more tumor-involved SNs, they were included in the analyses. All patients gave written informed consent, and all institutions obtained approval by their institutional review board. There were 165 investigators and 177 institutions participating in this study.Figure 1 illustrates the study schema.
Participants entered the study through two pathways, the most common of which was randomization post-SLND when the final histopathologic results of examination of the SN were known. However, some patients were pre-registered before SLND and then randomly assigned to a treatment arm intraoperatively by an interactive automated telephone system when frozen section or touch preparation analysis documented a tumor-involved SN. Although some of these patients were subsequently found to have three or more tumor-involved SNs, they were included in the analyses. All patients gave written informed consent, and all institutions obtained approval by their institutional review board. There were 165 investigators and 177 institutions participating in this study.
