Shear-wave elastography-based nomograms predicting 21-gene recurrence score for adjuvant chemotherapy decisions in patients with breast cancer

Purpose: To develop and validate nomograms based on shear-wave elastography (SWE) combined with clinicopathologic features for predicting Oncotype DX recurrence score (RS) for use with adjuvant systemic therapy guidelines. Methods: In a retrospective study, patients with breast cancer who underwent definitive surgery of the breast between August 2011 and December 2019 were eligible for this study. Those with surgery between August 2011 and March 2019 were assigned to a development set and the rest were assigned to an independent validation set. Clinicopathologic features and SWE elasticity indices were assessed with logistic regression to develop nomograms for predicting RS >= 16 and >= 26. Analysis of the area under the receiver operating characteristic curve (AUROC) was used to assess the performance of the nomograms. Results: Of a total 381 women (mean age, 51 +/- 9 years), 286 (mean age, 51 +/- 9 years) were in the development set and 95 (mean age, 51 +/- 9 years) in the validation set. All SWE elasticity indices were independently associated with each RS cutoff (odds ratio, 1.006-1.039 for RS >= 16; odds ratio, 1.008-1.076 for RS >= 26). Nomograms based on SWE combined with clinicopathologic features were developed and validated for RS >= 16 (mean elasticity [AUROC, 0.74; 95% CI: 0.68, 0.80] and maximum elasticity [AUROC, 0.74; 95% CI: 0.69, 0.80]) and for RS >= 26 (mean elasticity [AUROC, 0.81; 95% CI: 0.73, 0.89], maximum elasticity [AUROC, 0.82; 95% CI: 0.74, 0.89], and elasticity ratio [AUROC, 0.86; 95% CI: 0.80, 0.93]). Conclusion: Nomograms based on SWE can predict Oncotype DX RS for use in adjuvant systemic therapy decisions.