Measurement of tissue mechanical characteristics to distinguish between benign and malignant prostatic disease

To investigate the relationship between the morphology and mechanical properties of benign and malignant prostatic tissues measured in vitro.

Fresh tissue specimens were collected from patients undergoing transurethral resection of the prostate (TURP) for benign or malignant prostatic enlargement. Individual TURP chippings underwent immediate mechanical testing by applying a dynamic compressive strain to the samples. The amplitude ratio (E*) and phase difference (tan delta), measures of tissue elastic and viscous components respectively, were derived. Individual sections from the processed specimens underwent immunohistochemical staining and computerized image analysis was used to measure the morphologic characteristics of each TURP chipping. Linear regression analysis was used to assess correlations between morphologic and mechanical measurements, and the unpaired t test, assuming equal variances, was used to compare the mechanical and morphologic characteristics of benign and malignant prostates.

Significant differences were noted between the morphology of the benign and malignant prostates. Tan delta was significantly smaller within the malignant prostates (P = 001). No difference was found between the benign and malignant prostates with respect to E*. Within the malignant prostates, a strong negative correlation was found between the epithelial tissue content and tan delta (R2 = 0.50, P = 0.031).

The results of this study showed that measurable differences exist between the mechanical characteristics of benign and malignant prostatic tissue and provide further evidence that significant correlations exist between prostatic tissue morphology and mechanical characteristics. We believe that the ability to quantify prostatic tissue mechanical characteristics in vivo may be of clinical benefit in the future assessment of prostatic diseases, both benign and malignant.