Performance Characteristics of Transrectal Shear Wave Elastography Imaging in the Evaluation of Clinically Localized Prostate Cancer: A Prospective Study

Abstract

We tested the diagnostic accuracy of shear wave elastography to detect and phenotypically characterize prostate cancer compared with whole mount radical prostatectomy histopathology. In this prospective, protocol driven, diagnostic accuracy study 212 consecutive men undergoing laparoscopic radical prostatectomy for clinically localized prostate cancer were recruited. Quantitative stiffness data on the prostate gland were obtained in each patient using an endocavitary transrectal transducer before laparoscopic radical prostatectomy. Those data were compared with a detailed histopathological examination of the radical prostatectomy specimen using 3-dimensional printing mold based technology to ensure an improved image histology orientation. ROC curves were assessed between the groups. Quantitative stiffness data estimated in kPa were significantly higher in malignant compared with benign areas. At a cutoff of 82.6 kPa the sensitivity and specificity of shear wave elastography were 96.8% and 67.8%, respectively (p<0.01). Significant differences were observed for different cancer grades with the Young moduli, including 91.6, 102.3 and 131.8 kPa for low grade (Gleason score 6), intermediate grade (Gleason score 7) and high grade (Gleason score 8 or greater) prostate cancer, respectively (p <0.05). Shear wave elastography also detected capsular breaches with significant prediction of prostate cancer pathological staging. Potential limitations include selection bias and study being single center site. Quantitative shear wave elastography via the transrectal approach accurately detected cancer foci and revealed significant differences between cancerous and benign tissue. Moreover, this technique can be used to reliably phenotype prostate cancer aggressiveness.