De-escalating Axillary Surgery in Breast Cancer

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • Where we are now (2025):
    • In carefully selected cT1 to cT2, cN0 patients with negative pre-op axillary US:
      • Omitting SLNB is non-inferior to SLNB for disease endpoints and reduces arm morbidity:
        • SOUND Trial , INSEMA Trial; endorsed in ASCO 2025
    • If SLN is positive (≤ 2 nodes) after lumpectomy + WBRT:
      • Omit ALND (ACSOG Z0011, 10-yr)
    • For micrometastases:
      • IBCSG 23-01 supports no ALND
    • AMAROS:
      • Axillary RT ≈ ALND for control with less lymphedema
    • Post-NAC cN1→cN0:
      • SLNB / TAD feasible if you remove the clipped node, use dual tracers, and retrieve ≥2–3 SLNs:
        • Lower FNR:
          • ACSOG Z1071 / SENTINA / SN-FNAC
    • Persistent cN+ → ALND
    • Radiation interfaces (2025 ASTRO-ASCO-SSO PMRT update) – Clarify when RNI / PMRT substitutes for completion ALND after positive SLN, and after NAC:
      • What de-escalation buys you:
        • Meaningfully less lymphedema and arm morbidity:
          • AMAROS 5-year lymphedema: 23% ALND vs 11% axillary RT; SLNB is lower still; omission (SOUND / INSEMA) lowest
          • INSEMA: omission vs SLNB—lower arm symptoms; 5-yr iDFS 91.9% vs 91.7% (HR 0.91; NI met). 
  • Trial data:
    • Upfront surgery, cN0:
      • SOUND (JAMA Oncol 2023) – negative axillary US, tumor ≤ 2 cm
        • Design: SLNB vs no axillary surgery
        • Outcome: Non-inferior 5-yr distant DFS
        • Omission safe when nodal information won’t alter plan
        • Multinational, 18 centers (Italy / Spain / Switzerland / Chile)
      • INSEMA (NEJM 2025) – mostly BCS, cT1 to 2 cN0
        • Primary: 5-yr iDFS non-inferiority met (No axillary surgery 91.9% vs SLNB 91.7%; HR 0.91 [0.73–1.14])
        • OS ~ 98% vs 97%
        • Less arm morbidity if omitted
    • ASCO 2025 SLNB guideline update:
      • Allows omission of routine SLNB in selected stage I to II patients: ≥ 50 y, HR+ / HER2−, ≤ 2 cm, G1 to G2, negative axillary imaging, BCS + adjuvant therapy, and when nodal status won’t change systemic / RT
        • Shared decision-making emphasized
      • Limited SLN positivity (upfront):
        • ACSOG Z0011 (10-yr) – lumpectomy + WBRT, 1 to 2 positive SLN
          • 10-yr OS: 86.3% SLNB-alone vs 83.6% ALND
          • Regional failures < 1%
          • ALND not routine recommended 
        • IBCSG 23-01 (10-yr) – SLN micromets ≤ 2 mm:
          • No difference DFS; non-inferior to omit ALND
          • Axillary recurrences ~ 1.7% without cALND at 10 yrs
        • AMAROS – SLN+ randomized to ALND vs axillary RT:
          • Comparable control
          • Less lymphedema with RT (≈ 11% vs 23% at 5 yrs)
          • Consider RT instead of ALND
        • Neoadjuvant setting:
          • Z1071 / SENTINA / SN-FNAC – initially cN1→NAC→ycN0
          • FNR reduced by: clip + retrieve positive node (TAD), dual tracer, and retrieving ≥ 2 to 3 SLNs
          • If still cN+, ALND remains standard.
        • Radiation guidance (2025)
          • ASTRO-ASCO-SSO PMRT update (2025)
            Clarifies PMRT / RNI after upfront surgery and after NAC
          • Indicates when axillary RT is reasonable alternative to ALND in select SLN+ scenarios
          • Encourages moderate hypofractionation, details target volumes/boost
    • Practical algorithms (evidence-based):
      • Upfront cN0 (exam + negative axillary US):
        • Meets ASCO 2025 “omission” profile (≥ 50, HR+ / HER2−, ≤ 2 cm, G1 to G2) and BCS planned → Discuss omitting SLNB (SOUND Trial /INSEMA Trial) 
        • Not low-risk or mastectomy planned → SLNB (can later omit ALND depending on path)
      • SLNB results (upfront surgery):
        • 0 nodes+ → No further axillary surgery
        • 1 to 2 nodes+, lumpectomy + WBRT → Omit ALND (Z0011) or Axillary RT (AMAROS) if nodal coverage desired
        • Micromets (≤ 2 mm) → No ALND (IBCSG 23-01)
        • > 2 nodes+, gross ENE, no RT planned /possible, inflammatory BC, or T3 / T4 → ALND (plus consider RNI / PMRT)
      • NAC pathway:
        • Biopsy-proven cN1 → Clip positive node pre-NAC:
          • ycN0 after NAC → TAD (SLNB + clipped node removal) using dual tracer, aim ≥ 2 to 3 SLNs
          • If any positive or clip not retrieved, strong consideration for ALND (or RNI per MDT)
        • ycN+ → ALND (then RNI per PMRT guideline)
    • Numbers and pearls slide:
      • INSEMA:
        • 5-yearr iDFS 91.9% (omit) vs 91.7% (SLNB); HR 0.91 (NI met)
        • Lower arm morbidity with omission
      • SOUND:
        • Negative US + small tumors → no axillary surgery non-inferior to SLNB for distant DFS at 5 yrs
      • Z0011 (10-yr):
        • OS 86.3% SLNB-alone vs 83.6% ALND; regional recurrence < 1%
      • IBCSG 23-01 (10-yr):
        • Micromets – no ALND
        • Axillary recurrence ≈ 1.7% without cALND
      • AMAROS:
        • Lymphedema 23% ALND vs 11% axillary RT (5 yrs)
        • Similar control
      • Post-NAC accuracy:
        • TAD + dual tracer + ≥ 2 to 3 SLNs lowers FNR (vs SLNB alone)
      • ASTRO-ASCO-SSO 2025 PMRT:
        • When SLN+ and no ALND, RNI/PMRT often appropriate; specifics by burden / response 
  • Review Questions:
  • Can I omit SLNB in a 62-year-old, HR+ / HER2−, 1.3 cm IDC, negative axillary US, BCS?
    • Yes, option to omit per ASCO 2025 (criteria met) informed by SOUND and INSEMA; confirm that nodal information won’t change systemic / RT plan
  • What if the same patient is having a mastectomy
    • Generally perform SLNB (you lose SLNB opportunity later; pathology could upstage; influences RNI / PMRT)
  • Patient with 2 SLN+ undergoing lumpectomy – ALND or RT?
    • No routine ALND (Z0011)
    • Consider axillary RT (AMAROS) if you want nodal coverage with less lymphedema than ALND
  • Post-NAC cN1→ycN0 – how do I minimize FNR?
    • Do TAD: clip and retrieve the index node, dual tracers, retrieve ≥ 2 to 3 SLNs
    • If clip not found or any positive nodes → ALND (or RNI per MDT)
  • Which patients still truly need ALND today
    • Inflammatory BC
    • Persistent cN+ after NAC
    • > 2 SLN+ upfront
    • Gross ENE
    • When WBRT / RNI not feasible but regional control is required
  • How do the new PMRT guidelines affect axillary surgery choices?
    • 2025 ASTRO-ASCO-SSO:
      • Clearer indications for RNI / PMRT after upfront surgery and after NAC
      • Can replace ALND in select SLN+ cases – coordinate with radiation oncology




         
         
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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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