Performance characteristics of transrectal shear wave elastography (SWE) imaging in the evaluation of clinically localised prostate cancer: a prospective study

Objective: To test the diagnostic accuracy of SWE for the detection and phenotypic characterisation of PCa compared with whole-mount radical prostatectomy histopathology.

Materials and Methods: This was a prospective protocol-driven diagnostic accuracy study. 212 consecutive men undergoing laparoscopic radical prostatectomy (LRP) for clinically localised PCa were recruited into the study. Quantitative stiffness data of the prostate gland was obtained in each patient using an endocavitary transrectal transducer before LRP and compared with detailed histopathological examination of radical prostatectomy specimen using 3-D printing mold based technology ensuring improved image-histology orientation. Receiver operator characteristic curves (ROC) were assessed between the groups.

Results and limitations: Quantitative stiffness data estimated in kilopascals (kPa) was significantly higher in malignant compared with benign areas. With a cut-off value of 82.6 kPa, sensitivity and specificity of SWE were 96.8% and 67.8%, respectively (p<0.05). Significant differences were observed for different grades of cancer with Young’s moduli 91.6kPa, 102.3kPa and 131.8kPa for low (Gleason score 6), intermediate (Gleason score 7) and high grade (Gleason score ≥ 8) PCa respectively (p<0.05). SWE also detected capsular breaches with significant prediction of PCa pathologic staging. Potential limitations include selection bias and study being single centre site.

Conclusions: Quantitative SWE via transrectal approach accurately detected cancer foci and showed significant differences between cancerous and benign tissue. Moreover, this technique can be used to reliably phenotype PCa aggressiveness.