Axillary Pathologic Complete Response (PCR) in ER+ / HER 2- Breast Cancer

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • Axillary pCR in ER⁺ / HER2⁻ Breast Cancer after neoadjuvant chemotherapy (NACT):
    • Neoadjuvant chemotherapy is commonly used to downstage axillary disease in node-positive breast cancer:
      • However, ER – positive, HER2 – negative tumors:
        • Especially luminal A subtype:
          • Are less responsive to chemotherapy compared to triple-negative or HER2-positive tumors
Axillary Response to Neoadjuvant Chemotherapy
  • Interpretation and Considerations:
    • Luminal A tumors (low Ki-67):
      • Typically show < 10% pCR
    • Luminal B tumors (higher proliferative index):
      • Achieve up to 20% to 25% axillary pCR
    • Hormone receptor positivity:
      • Correlates inversely with chemotherapy response
    • Axillary response:
      • May exceed breast pCR in some ER+ / HER2− patients:
        • Isolated nodal clearance
    • Ki-67 and genomic assays (e.g., Oncotype DX, MammaPrint):
      • May predict likelihood of response
  • Clinical Implications:
    • Lower pCR in ER+ / HER2-:
      • Supports careful use of NACT primarily for:
        • Tumor downsizing in borderline resectable disease
        • Downstaging axilla to avoid ALND:
          • If cN1 → ypN0
        • Surgical planning should consider likelihood of residual disease:
          • Particularly in low-proliferative tumors
    • Role for post-NACT axillary imaging and sentinel lymph node biopsy remains critical in this group
  • Key References:
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Published by Rodrigo Arrangoiz MS, MD, FACS, FSSO

My name is Rodrigo Arrangoiz I am a breast surgeon/ thyroid surgeon / parathyroid surgeon / head and neck surgeon / surgical oncologist that works at Center for Advanced Surgical Oncology in Miami, Florida. I was trained as a surgeon at Michigan State University from (2005 to 2010) where I was a chief resident in 2010. My surgical oncology and head and neck training was performed at the Fox Chase Cancer Center in Philadelphia from 2010 to 2012. At the same time I underwent a masters in science (Clinical research for health professionals) at the University of Drexel. Through the International Federation of Head and Neck Societies / Memorial Sloan Kettering Cancer Center I performed a two year head and neck surgery and oncology / endocrine fellowship that ended in 2016. Mi nombre es Rodrigo Arrangoiz, soy cirujano oncólogo / cirujano de tumores de cabeza y cuello / cirujano endocrino que trabaja Center for Advanced Surgical Oncology en Miami, Florida. Fui entrenado como cirujano en Michigan State University (2005 a 2010 ) donde fui jefe de residentes en 2010. Mi formación en oncología quirúrgica y e n tumores de cabeza y cuello se realizó en el Fox Chase Cancer Center en Filadelfia de 2010 a 2012. Al mismo tiempo, me sometí a una maestría en ciencias (investigación clínica para profesionales de la salud) en la Universidad de Drexel. A través de la Federación Internacional de Sociedades de Cabeza y Cuello / Memorial Sloan Kettering Cancer Center realicé una sub especialidad en cirugía de cabeza y cuello / cirugia endocrina de dos años que terminó en 2016.

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