Potentials and Limitations of Real-Time Elastography for Prostate Cancer Detection: A Whole-Mount Step Section Analysis

Abstract

Objectives. To evaluate prostate cancer (PCa) detection rates of real-time elastography (RTE) in dependence of tumor size, tumor volume, localization and histological type. Materials and Methods. Thirdy-nine patients with biopsy proven PCa underwent RTE before radical prostatectomy (RPE) to assess prostate tissue elasticity, and hard lesions were considered suspicious for PCa. After RPE, the prostates were prepared as whole-mount step sections and were compared with imaging findings for analyzing PCa detection rates. Results. RTE detected 6/62 cancer lesions with a maximum diameter of 0–5 mm (9.7%), 10/37 with a maximum diameter of 6–10 mm (27%), 24/34 with a maximum diameter of 11–20 20 mm (70.6%), 14/14 with a maximum diameter of >20 mm (100%) and 40/48 with a volume ≥0.2 cm3 (83.3%). Regarding cancer lesions with a volume ≥ 0.2 cm³ there was a significant difference in PCa detection rates between Gleason scores with predominant Gleason pattern 3 compared to those with predominant Gleason pattern 4 or 5 (75% versus 100%; P = 0.028). Conclusions. RTE is able to detect PCa of significant tumor volume and of predominant Gleason pattern 4 or 5 with high confidence, but is of limited value in the detection of small cancer lesions.

Real-Time Elastography of the Prostate

“…For diffusion-weighted MRI (DWI), Langer et al demonstrated that all “invisible” tumours in DWI had predominant Gleason pattern 3 and showed sparse architecture on histology [26]. For RTE, we revealed similar results, since RTE visualises cancer due to the higher cell density compared to the normal surrounding tissue [13, 27]. Nearly all cancers missed on RTE in our study population with a significant tumour volume were also of sparse architecture and had predominant Gleason pattern 3.…”

Comparison of Real-Time Elastography and Multiparametric MRI for Prostate Cancer Detection: A Whole-Mount Step-Section Analysis

“…In general, imaging of prostate cancer is limited by tumor volume (size) and grade, because cancers with a predominant Gleason pattern of 3 (i.e., Gleason score of 6 with 3 + 3 or of 7 with 3 + 4) are intermixed with normal glands and glands with dilated lumina (sparse tumors) [7,17,18]. Delongchamps et al [16] used a similar multiparametric MRI setting with an endorectal coil at 1.5 T and for prostate cancers with volumes greater than 0.2 cm 3 reported a sensitivity of 80% for the peripheral zone and 53% for the transitional zone, which are in concordance with our results.…”

Strain Elastography of Breast and Prostata Cancer: Similarities and Differences

“…In contrast, there is a finding of a suspicious tumor of the prostate if a hardened area > 5 mm can be reproduced on two different planes [32]. For example, sensitivity of 9.7 % could be shown for prostate cancer with maximum diameters of 0 -5mm; 27 % for prostate cancer with maximum diameters of 6 -10mm; 70.6 % for prostate cancer with maximum diameters of 11 -20mm; and 100 % for prostate cancer with maximum diameters of > 20 mm [30].…”

“…This type of histological tumor composition in generally found in prostate cancer with primary Gleason pattern 3 (G6 (3 + 3) or G7 (3 + 4)). Above G7 (4 + 3), USE sensitivity for prostate cancer detection is very high, since this cancer type is very compact as a rule (dense architecture) [30]. Since prostate cancer ≤ G7 (3 + 4) is considered insignificant, and significant if greater than G7 (4 + 3), USE particularly appears to be a possible technology to reduce the much-criticized over-diagnosis and over-treatment of this cancer [31].…”

“…If the prostate cancer tumor is made up of glands with dilated lumina containing substantial mucus or contains sparse architecture, then such tumors can avoid detection by both DRU as well as USE, due to increased tissue elasticity [29,30]. This type of histological tumor composition in generally found in prostate cancer with primary Gleason pattern 3 (G6 (3 + 3) or G7 (3 + 4)).…”