Performance of Mid-Treatment Breast Ultrasound and Axillary Ultrasound in Predicting Response to Neoadjuvant Chemotherapy by Breast Cancer Subtype.
The primary objective was to determine whether mid-treatment ultrasound measurements of index breast tumors and index axillary nodes of different cancer subtypes associate with residual cancer burden (RCB).



Patients with invasive breast cancer who underwent neoadjuvant chemotherapy and had pre-treatment and mid-treatment breast and axillary ultrasound were included in this single-institution, retrospective cohort study. Linear regression analysis assessed associations between RCB with (a) change in index breast tumor size, (b) change in index node size, and (c) absolute number of abnormal nodes at mid-treatment. Multivariate linear regression was used to calculate best-fit models for RCB.



One hundred fifty-nine patients (68 triple negative breast cancer [TNBC], 45 hormone receptor [HR]+/human epidermal growth factor receptor 2 [HER2]-, and 46 HR-/HER2+) were included. Median age at diagnosis was 50 years, range 30-76. Median tumor size was 3.4 cm, range 0.9-10.4. Pathological complete response/RCB-I rates were 36.8% (25/68) for TNBC patients, 24.4% (11/45) for HR+/HER2- patients, and 71.7% (33/46) for HR-/HER2+ patients. Linear regression analyses demonstrated associations between percent change in tumor ultrasound measurements at mid-treatment with RCB index score in TNBC and HR+/HER2- (p< .05) but not in HR-/HER2+ (p> .05) tumors and an association between axillary ultrasound assessment of number of abnormal nodes at mid-treatment with RCB index score across all subtypes (p< .05).



Performance characteristics of breast ultrasound associated with RCB vary by cancer subtype, whereas the performance characteristics of axillary ultrasound associated with RCB are consistent across cancer subtype. Breast and axillary ultrasound may be valuable in monitoring response to neoadjuvant therapy.The Oncologist2017;22:394-401 IMPLICATIONS FOR PRACTICE: The differential performance characteristics of breast ultrasound by molecular subtype and the consistent performance characteristics of axillary ultrasound across molecular subtypes can have clinical utility in monitoring response to neoadjuvant therapy.
Department of Diagnostic Radiology, Unit 1350 rcandelaria@mdanderson.org.
Rosalind P
RP
Candelaria
Department of Biostatistics, Unit 1411.
Roland L
RL
Bassett
Department of Pathology, Unit 1445.
William Fraser
WF
Symmans
Department of Pathology, Unit 1445.
Maheshwari
M
Ramineni
Department of Breast Medical Oncology, Unit 1354.
Stacy L
SL
Moulder
Department of Breast Surgical Oncology, Unit 1434, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Henry M
HM
Kuerer
Department of Breast Surgical Oncology, Unit 1434, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Alastair M
AM
Thompson
Department of Diagnostic Radiology, Unit 1350.
Wei Tse
WT
Yang
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000145:classification / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000009:adverse effects; D018365:Neoplasm, Residual; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D012189:Retrospective Studies; D016217:Ultrasonography, Mammary
D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
Breast cancer; Neoadjuvant therapy; Ultrasound