SOUND Trial – Journal Club Questions and Answers

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • What was the primary objective of the SOUND trial?
    • Answer:
      • To determine whether sentinel lymph node biopsy (SLNB) can be safely omitted in women with early-stage, clinically node-negative breast cancer with negative axillary ultrasound:
        • Without compromising distant disease-free survival
  • What does “SOUND” stand for in this trial?
    • Answer:
      • SOUND stands for:
        • Sentinel node vs Observation after axillary UltraSouND
  • What were the eligibility criteria for patients
    • Answer:
      • Women with unifocal invasive breast cancer ≤ 2.0 cm
      • Clinically node-negative
      • Negative axillary ultrasound (AUS)
      • Undergoing breast-conserving surgery
      • No prior neoadjuvant therapy
  • Describe the study design of the SOUND trial:
    • Answer:
      • Phase 3, multicenter, randomized non-inferiority trial
        • Two arms:
          • SLNB group vs. observation (no axillary surgery)
      • Primary endpoint:
        • 5-year distant disease-free survival (DDFS)
  • What was the primary endpoint, and how was non-inferiority defined?
    • Answer:
      • Primary endpoint:
        • 5-year distant disease-free survival (DDFS)
      • Non-inferiority margin:
        • Upper bound of 95% CI for the hazard ratio had to be ≤ 1.50
  • What were the key results of the SOUND trial
    • Answer:
      • 5-year DDFS:
        • 95.5% (observation) vs. 96.2% (SLNB)
      • Non-inferiority was demonstrated
      • No significant difference in axillary recurrence or overall survival
  • What does this trial suggest about the role of SLNB in modern breast cancer management?
    • Answer:
      • SLNB may be safely omitted in carefully selected patients with low-risk, early-stage breast cancer and negative AUS:
        • Reinforcing a less invasive, de-escalated approach
  • What were the secondary outcomes, and how did they compare?
    • Answer:
      • Overall survival:
        • No difference:
          • OS at 5 yr: 
            • 98.4% vs 98.2%
      • Axillary recurrence:
        • < 1.5% in both arms
      • Quality-of-life data (previous reports) favored the observation group
  • What is the clinical significance of using axillary ultrasound as a triage tool?
    • Answer:
      • Axillary ultrasound helps identify patients who do not need SLNB, reducing unnecessary surgery in node-negative disease with high diagnostic accuracy
  • How does the SOUND trial compare to ACOSOG Z0011 and INSEMA?
    • Answer:
      • ACOSOG Z0011:
        • Tested omission of ALND after positive SLNB
      • INSEMA:
        • Tested omission of SLNB in cN0 patients undergoing BCS + radiation
      • SOUND:
        • Focused on completely omitting axillary surgery in AUS-negative patients
  • What were some exclusion criteria in the trial
    • Answer:
      • Multifocal or multicentric disease
      • Tumors > 2.0 cm
      • Mastectomy patients
      • Neoadjuvant therapy
      • Prior axillary surgery
  • What were some limitations of the SOUND trial
    • Answer:
      • Limited to low-risk patients
      • Mostly postmenopausal, HR-positive / HER2-negative tumors
      • Not generalizable to mastectomy, young, or high-risk patients
  • How might omission of SLNB affect decisions about adjuvant systemic therapy?
    • Answer:
      • Without nodal staging, oncologists may rely more on tumor biology, imaging, and genomic testing to guide chemotherapy decisions
  • What were the main benefits of omitting SLNB noted in the trial?
    • Answer:
      • Reduced risk of lymphedema
      • Better arm mobility
      • Improved quality of life
      • Shorter operative times and fewer complications
  • Based on SOUND, how would you counsel a 62-year-old woman with a 1.5 cm ER+ / HER2 negative tumor and negative axillary ultrasound?
    • Answer:
      • She is a candidate for SLNB omission:
        • I would explain that observation is safe, doesn’t affect survival, and lowers surgical risk, but the decision should involve the oncology team to ensure systemic therapy isn’t compromised
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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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