SOUND.

Trial name or title	SOUND (Sentinel node vs Observation After Axillary UltraSouND)
Methods	Study design: RCT Country: Italy
Participants	Inclusion criteria: breast cancer ≤ 2 cm and clinically negative axilla, any age, candidates to receive breast‐conserving surgery + radiotherapy, negative preoperative assessment of the axilla (ultrasound with or without FNAC in case 1 doubtful node is found), written informed consent must be signed and dated by the participant and the investigator before inclusion, patients must be accessible for follow‐up Exclusion criteria: synchronous distant metastases, previous malignancy, bilateral breast cancer, multi‐centric or multi‐focal breast cancer, previous primary systemic therapy, pregnancy or breastfeeding, preoperative diagnosis (cytology or histology) of axillary lymph node metastases, preoperative radiological evidence of multiple involved or suspicious nodes, patients with psychiatric/addictive/any disorder that compromises the ability to give informed consent for participation in the study
Interventions	SLND with axillary dissection in the presence of macrometastases diagnosed in the sentinel lymph node and SLND without axillary dissection in the case of negative sentinel lymph node or in the presence of isolated tumour cells or micrometastases vs no axillary surgical staging
Outcomes	Distant disease‐free survival, cumulative incidence of distant recurrences, cumulative incidence of axillary recurrences, disease‐free survival, overall survival, quality of life, evaluation of type of adjuvant treatment administered
Starting date	2012
Contact information	Oreste Gentilini, oreste.gentilini@ieo.it
Notes

ALND: axillary lymph node dissection.
 FNAC: fine‐needle aspiration cytology.
 RCT: randomised controlled trial.
 SLN: sentinel lymph node.
 SLNB: sentinel lymph node biopsy.