The SOUND trial investigated the oncological safety of omitting sentinel lymph node biopsy (SLNB) in early breast cancer with clinically and ultrasound-negative axilla. Its primary endpoint was:
- A Non-inferiority in distant disease-free survival at 5 years ✓
- B Disease-free survival at 5 years — non-inferior in the no-SLNB arm
- C Axillary recurrence rate at 10 years — equivalent in both arms
- D Patient-reported shoulder morbidity significantly reduced without SLNB
Correct answer: A. Non-inferiority in distant disease-free survival at 5 years
Explanation
The SOUND trial randomized patients with T1 breast cancer and ultrasound-negative axilla to SLNB versus no axillary surgery. Its primary endpoint was distant disease-free survival (DDFS) at 5 years, demonstrating non-inferiority of omitting SLNB (DDFS 97.7% vs 98.0%). This indicates that in carefully selected patients (T1, clinically/US node-negative), skipping SLNB does not compromise outcomes. The trial supports omission of SLNB as a practice-changing de-escalation strategy in appropriate patients.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.