Jung Min Chang MD, Abstract Co-Author: Nothing to Disclose

Su Hyun Lee MD, Presenter: Nothing to Disclose

Woo Kyung Moon, Abstract Co-Author: Nothing to Disclose

Hye Ryoung Koo MD, Abstract Co-Author: Nothing to Disclose

Ann Yi MD, Abstract Co-Author: Nothing to Disclose

Nariya Cho MD, Abstract Co-Author: Nothing to Disclose

To investigate the correlation of maximum stiffness values on shear-wave elastography (SWE) and tumor receptor status (i.e., estrogen receptor[ER], progesterone receptor[PR], and human epidermal growth factor receptor 2[HER2]), size, histology, and grade.

This was an institutional review board–approved retrospective study with waiver of informed consent. A total of 229 invasive breast cancers in 220 women (mean age, 52.5±9.3) were included. Prospectively recorded tumor size at gray scale US, and mean elasticity in terms of the Young’s modulus (in kilopascals, kPa) of the stiffest portion at SWE were recorded. Pathology reports were reviewed to establish the histologic type, grade, and receptor status. Mean elasticity values according to tumor receptor status, size, histology, and grade were analyzed using one-way ANOVA, Fisher’s exact test and multiple linear regression analysis.  

Mean tumor size was 2.3 cm±1.2 and mean elasticity values were 153.3 kPa±58.1. Among the histopathologic subtypes, there were 198 infiltrating ductal, 14 lobular, 7 mixed ductal-lobular, 3 papillary, 4 metaplastic, 1 mucinous, micropapillary and apocrine carcinoma. No significant differences were noted between tumor histology. When tumors were divided into four subtypes (i.e., luminal A [ER+/HER2-], luminal B [ER+/HER2+], HER2 positive [ ER-/HER 2+] and triple negative [ER-,PR-,HER2-]), HER2 positive (168.2 kPa±55.2) and triple negative (172.8 ± 50.4) tumors showed higher average mean elasticity values than luminal A tumors (137.6±58.6, P=0.002). When all subgroups were compared according to tumor size and histologic grade, mean elasticity values were significantly lower in luminal A tumors than HER2 positive or triple negative tumors in group of tumor smaller than 2.5cm (P=0.01). Multiple linear regression analysis revealed that tumor size (P< 0.0001) and histologic grade (P=0.008) in infiltrating ductal carcinoma were independent factors determining mean elasticity values, and degree of ER positivity (P=0.037) was inversely correlated with mean elasticity values on SWE in grade III infiltrating ductal carcinoma.       

Luminal A tumors showed the lowest mean elasticity values whereas tumors with larger size, higher histologic grade and triple negative phenotype showed higher mean elasticity values.

SWE may be helpful in detecting breast cancers with aggressive phenotype.

Chang, J, Lee, S, Moon, W, Koo, H, Yi, A, Cho, N, Stiffness Values Measured by Shear-wave Elastography Correlated with Aggressive Breast Cancer Phenotype.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12031199.html