Axillary dissection in women with sentinel node metastasis

Randomised trials published over 15 years ago established local excision, level I and II axillary lymph node dissection (ALND), and whole breast radiotherapy as appropriate locoregional treatment for women with early stage breast cancer. The recent publication of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial will reduce the use of ALND in women with positive sentinel lymph node biopsy (SLNB).1 The ACOSOG Z0011 trial compared ALND or no ALND in women with clinically negative axilla, no more than two sentinel lymph nodes affected (with no gross extracapsular extension), and primary tumour less than 5 cm who received lumpectomy, postoperative whole breast radiation, and appropriate systemic treatment.1 The trial was timely because about a third of women with a positive SLNB in the United States during the time of enrolment (1999-2005) did not undergo completion ALND after SLNB despite guidelines recommending it.2 As a non-inferiority trial, 1900 patients were needed to show with 90% confidence that the hazard ratio for overall survival did not include 1.3 in the patients who had no ALND, with final analysis after 500 deaths. Because the mortality rate in both arms was lower than expected, an independent data and safety monitoring committee recommendation resulted …