Objective: To discuss the correlation between quantitative shear wave elastography (SWE) and axillary lymph node metastasis and compare different quantitative methods of shear wave elastography to obtain the better quantitative parameters. Methods: Data were prospectively analyzed from 304 consecutive patients with invasive breast cancer who had undergone SWE examination and treated by primary surgery. Four elastography images—in each of two orthogonal planes—were taken of each lesion using the Aixplorer ultrasound system. Quantitative measurements were produced and analysed by Q-box trace and Q-box. Take the average number of two orthogonal planes as Emean, Emax and SD. Associations between lymph node involvement and mean lesion stiffness, invasive cancer size, tumour location, histologic grade, tumour type, ER expression, PR expression, and HER-2 status were assessed using univariate and multivariate logistic regression. Results: At univariate analysis, invasive cancer size, tumour location, ER, PR, HER-2 and stiffness value of different quantitative methods were significantly associated with nodal involvement. At multivariate analysis, invasive size (P<0.001), HER-2 (P=0.002), SD (P=0.001) of Q-box trace and Mmean (P=0.028) of Q-box maintained independent significance.
Conclusion: Stiffness parameters of SWE are independent predictors of lymph node metastasis and thus can confer prognostic information additional to that provided by preoperative tumour and lymph node assessment and staging.