Value of shear-wave elastography in the diagnosis of symptomatic invasive lobular breast cancer

Aim: To investigate the contribution of shear-wave elastography (SWE) in diagnosing invasive lobular breast cancer (ILC) in symptomatic patients.Materials and methods: A retrospective case-controlled study of 52 patients with ILC and 52 patients with invasive ductal cancer (IDC), matched for age and tumour size, was performed. Breast density and mammographic and greyscale ultrasound features were graded using Breast Imaging-Reporting and Data System (BI-RADS) classification by two radiologists, blinded to SWE and pathology findings. Forty-four benign lesions were also included. The sensitivity of SWE was assessed, using a cut-off value of 50kPa for mean elasticity. Statistical significance was evaluated using Chi-square and Chi-square for trend tests.Results: Mean age for both ILC and IDC groups was 67 years. Mean size for ILC was 44mm and IDC was 37mm. The sensitivity for detection of ILC and IDC for mammography, greyscale ultrasound, and SWE were 79% versus 87%, 87% versus 98%, 94% versus 100%, respectively. SWE had significantly higher sensitivities than mammography for the detection of both ILC and IDC (p = 0.012 and p = 0.001, respectively). SWE was not significantly more sensitive than greyscale ultrasound for the detection of either tumour type. Four (8%) lobular cancers were benign/normal at both mammography and greyscale ultrasound, but suspicious on SWE. The incremental gain in sensitivity by using SWE in ILC was statistically significant compared to IDC (p = 0.01).Conclusion: SWE can diagnose lobular cancers that have benign/normal findings on conventional imaging as suspicious.