Mid-NAC Ultrasound May Predict Response in Breast Cancer
Ultrasound findings at mid-NAC were associated with RCB among patients with TNBC and (HR)-negative, HER2-positive disease.
Editor's note: This article was updated on April 13, 2017 to correct the P-value in the fifth paragraph, which is ≤ .0001.
Ultrasound findings at mid-neoadjuvant (NAC) treatment of breast cancer were associated with residual cancer burden (RCB) among patients with triple-negative breast cancer (TNBC) and hormone receptor (HR)-negative, HER2-positive disease, according to a study published in The Oncologist.1
Molecular subtype may be a reason why previous studies demonstrated mixed results regarding differences in accuracy between ultrasound and MRI for monitoring treatment response. The purpose of this study was to evaluate the use of mid-treatment ultrasound to monitor response in different breast cancer subtypes.
In this retrospective study, data were collected from 159 patients with primary invasive breast cancer who received NAC chemotherapy and who had high-spatial resolution ultrasound images. Ultrasounds were analyzed for median tumor size, index lymph node size, and absolute number of abnormal lymph nodes. Associations with RDB were analyzed using logistic regression.
The molecular subtypes included TNBC, HR-positive, HER2-negative, and HR-negative, HER2-positive. Most patients had stage II (55.3%) or III (42.1%) disease. The median age at diagnosis was 50, and the median tumor size was 3.4 cm.
Among all patients, percent change in any ultrasound tumor or axillary node measurement was significantly associated with RCB index score (all P ≤ .0001). When stratified by molecular subtype, however, there was no significant association among patients with HR-negative, HER2-positive disease.
In the TNBC cohort, the greatest association was observed with percent change in axillary node volume, followed by change in tumor biodimension and change in tumor volume.
In the HR-positive, HER2-negative cohort, the highest association was observed with percent change in tumor volume, followed by change in tumor biodimension and change in tumor largest dimension.
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As a result of these findings, the authors “advocate the use of breast and axillary ultrasound in patients with TNBC or HR-positive/HER2-negative to evaluate the efficacy of NAC.”
- Candelaria RP, Bassett RL, Fraser Symmans W, et al. Performance of mid-treatment breast ultrasound and axillary ultrasound in predicting response to neoadjuvant chemotherapy by breast cancer subtype. Oncologist. 2017 Mar 17. doi: 10.1634/theoncologist.2016-0307 [Epub ahead of print]