Assessment of shear wave elastography for evaluating neoadjuvant chemotherapy efficacy in breast cancer: correlation of stiffness changes with pathological response

Background Accurate evaluation of neoadjuvant chemotherapy (NAC) efficacy is critical for optimizing breast cancer treatment. This study investigates shear wave elastography (SWE) for quantifying stiffness changes within lesions and peri-lesional tissues (1–3 mm) and correlating these changes with pathological response to NAC. Methods In a prospective cohort of 66 breast cancer patients, SWE parameters (Emax, Emean, Emin, Esd) were measured within tumors and surrounding tissues (1/2/3 mm) pre- and post-NAC. Pathological response was classified via Miller-Payne grading (G3-G5: effective; G1-G2: ineffective). Diagnostic performance was assessed using ROC curves. Results Post-NAC, the effective group exhibited significant reductions in Emax, Emean, and Esd within lesions and peri-lesional regions (all P < 0.05), while the ineffective group maintained high stiffness. ΔEmax showed high apparent discrimination of pathological response: Intralesional ΔEmax: AUC = 0.941 (95% CI: 0.887-0.995), sensitivity 88.89%, specificity 85.71% (cutoff >49.12%). Peri-lesional ΔEmax (1–3 mm): AUC > 0.9, specificity >90%. The stiff rim sign disappeared exclusively in the effective group post-NAC. Conclusion SWE parameters (especially ΔEmax) and dynamic changes in the stiff rim sign are promising non-invasive biomarkers that correlate with pathological response to NAC. These findings support the potential role of SWE in post-treatment response evaluation, though prospective validation in larger cohorts is warranted before clinical implementation.