Combination of ultrasonic elastography and Ki-67 index as a novel predictive modality for the prognosis in clinic stage III breast cancer

Abstract Background To investigate the feasibility of combination of ultrasonic elastography (UE) and Ki-67 index as a novel predictive modality for the prognosis of clinic stage Ⅲ breast cancer. Methods Of 112 patients, Multi-parameter of UE were obtained after analyzing elastograms of 112 lesions which were recorded classification of Ki-67 by histopathologic diagnosis. Multivariate Survival analysis was performed by using multivariate Cox model. The nomograms was established to predict the probability of clinic stage Ⅲ breast cancer according to the selected independently significant variables in the multivariate Cox model. The model was internally validated using Harrell’s concordance index. Results ⅢC had significant difference in all ultrasonic elastography (UE) parameters (P < 0.05) and were statistically different from ⅢA and ⅢB (P < 0.01). The Cox model was RR (t)= Exp(1.104* X1+0.901*X4+0.972*X5) (X1: classification of Ki-67, X4: classification of strain ratio, X5: classification of Young's modulus). The nomogram showed that Ki-67 had the greatest influence on survival prediction, followed by Young's modulus and strain ratio. Internal validation revealed a concordance index of 0.76. Conclusions Our study explored a novel modality in predicting the prognosis of clinic stage Ⅲ breast cancer combining a tumor marker with breast UE imaging. A nomogram was developed to prove that the model was helpful to estimate the 5-year survival of the patients.