Prediction of high nodal burden in invasive breast cancer by quantitative shear wave elastography

Axillary imaging has been earmarked to forecast high nodal burden [≥3 metastatic axillary lymph nodes (ALN)] instead of lymph node metastasis since the Z0011 trial period. We aimed to ascertain the possibility of utilising quantitative shear wave elastography (SWE) to forecast high nodal burden in invasive breast cancer (IBC).

In our hospital, 324 patients with clinical T1-T2N0 IBC who underwent surgery from June 2020 to October 2020 were analyzed retrospectively. A total of 273 patients (84.3%) were categorized as having a limited nodal burden, while 51 patients (15.7%) had a high nodal burden. The two groups were compared in terms of clinicopathological traits, ultrasonic features, and SWE values. The diagnostic performance for prediction of high nodal burden with the optimal cutoff values was drawn by SWE value.

The optimal cutoff values for forecasting high nodal burden were as demonstrated: 119.52 kPa for tumor Emax, 97.31 kPa for tumor Emean, 19.38 for tumor Esd, 26.22 kPa for ALN Emax, 19.79 kPa for ALN Emean, 2.32 for ALN Eratio, 3.34 for ALN Esd. Combined with the ratings of sensitivity and specificity, ALN Emax could be chosen as the optimal index if the best diagnostic achievement was contemplated (AUC: 0.856; 95% CI: 0.802-0.909).

An Emax cutoff 26.22 kPa of ALN, 72% of women with a high nodal burden of axillary disease would be detected, but if used for clinical decision making, 13% of women with a limited nodal burden disease would be potentially over treated. This data can allow us to appropriately ascertain this subgroup and can be used as one of the therapeutic implementation resources for patient decision support.