Sara Alkner, MD, Lund University, Lund, Sweden, discusses quality assurance in the SENOMAC trial (NCT02240472), which compared axillary lymph node dissection (ALND) and surveillance (sentinel lymph node biopsy only) in patients with clinically nodenegative breast cancer. Treatment plans of patients in Sweden or Denmark differed in inclusion of axillary level I nodes in the clinical target volume (CTV). Level I nodes were included in patients who did not receive ALND in Denmark, whereas inclusion was sitedependent in Swedish patients. Analysis of CTV revealed inclusion of axillary level I nodes made no significant difference in the interpretation of data. This interview took place at the European Society for Radiotherapy and Oncology (ESTRO) 2021.