CHICAGO -- Axillary ultrasound may help women with breast cancer avoid sentinel lymph node biopsy, suggest findings presented December 3 at RSNA 2025.
Retrospective analysis of the Sentinel Node vs. Observation After Axillary Ultra-Sound (SOUND) trial showed that after trial recommendations were applied, the false-negative rate for axillary ultrasound dropped by over 25%.
“We can see that ultrasound can be considered reliable for detecting significant nodal disease burden,” said Laura Abelairas Lopez, MD, from the Lucus Agusti University Hospital in Lugo, Spain, who presented the study results.
Laura Abelairas Lopez, MD, shares results at RSNA 2025 showing how axillary ultrasound can help predict significant nodal disease burden in breast cancer patients.
The SOUND trial was a prospective noninferiority phase III randomized clinical trial launched in 2012 and conducted in Italy, Switzerland, Spain, and Chile. It included 1,405 women with cT1cN0 breast cancer. Prior research suggests that axillary ultrasound is noninferior to sentinel lymph node biopsy. This goes for older, postmenopausal women with ER+, HER2-negative breast cancer who meet SOUND trial eligibility.
Lopez and colleagues studied whether omitting surgical axillary staging in women diagnosed with early breast cancer (cT1cN0) would affect chemotherapy adjuvant treatment.
The retrospective analysis included data from 283 women who underwent sentinel lymph node biopsy and primary breast surgery after a negative axillary ultrasound exam. Of the total cancers, 251 were invasive ductal carcinomas, 27 were invasive lobular carcinomas, and 25 were classified as “other.” And 258 of the total cancers with HER2-negative, while 268 were ER/PR-positive. Finally, 211 women in the study were postmenopausal.
Lopez reported the following findings:
Sentinel lymph node biopsy was positive in 61 women, meaning the false-negative rate of axillary ultrasound was 21.5%. For postmenopausal women, this rate was 20%.
Of the 61 women, 96.7% presented three or fewer positive nodes after axillary surgery. And 95.4% of the postmenopausal women in this group had three or fewer positive nodes after surgery.
Following the application of SOUND study recommendations, the false-negative rate of ultrasound dropped to 15% in postmenopausal women.
Five of the 211 postmenopausal women in the study would have missed chemotherapy based solely on axillary ultrasound information.
Lopez said the results confirm that axillary surgery could be safely avoided in women with small breast cancer and negative axillary ultrasound exams. And this would have little to no impact on adjuvant chemotherapy recommendations.
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