Computer-aided transrectal ultrasound: does prostate HistoScanning™ improve detection performance of prostate cancer in repeat biopsies?

A systematic review and meta-analysis of Histoscanning™ in prostate cancer diagnostics

CONTEXT

The value of Histoscanning™ (HS) in prostate cancer (PCa) imaging is much debated, although it has been used in clinical practice for more than 10 years now.

OBJECTIVE

To summarize the data on HS from various PCa diagnostic perspectives to determine its potential.

MATERIALS AND METHODS

We performed a systematic search using 2 databases (Medline and Scopus) on the query "Histoscan*". The primary endpoint was HS accuracy. The secondary endpoints were: correlation of lesion volume by HS and histology, ability of HS to predict extracapsular extension or seminal vesicle invasion.

RESULTS

HS improved cancer detection rate "per core", OR = 16.37 (95% CI 13.2; 20.3), p < 0.0001, I² = 98% and "per patient", OR = 1.83 (95% CI 1.51; 2.21), p < 0.0001, I² = 95%. The pooled accuracy was markedly low: sensitivity - 0.2 (95% CI 0.19-0.21), specificity - 0.12 (0.11-0.13), AUC 0.12. 8 of 10 studiers showed no additional value for HS. The pooled accuracy with histology after RP was relatively better, yet still very low: sensitivity - 0.56 (95% CI 0.5-0.63), specificity - 0.23 (0.18-0.28), AUC 0.4. 9 of 12 studies did not show any benefit of HS.

CONCLUSION

This meta-analysis does not see the incremental value in comparing prostate Histoscanning with conventional TRUS in prostate cancer screening and targeted biopsy. HS proved to be slightly more accurate in predicting extracapsular extension on RP, but the available data does not allow us to draw any conclusions on its effectiveness in practice. Histoscanning is a modification of ultrasound for prostate cancer visualization. The available data suggest its low accuracy in screening and detecting of prostate cancer.

Application of ultrasound imaging biomarkers (HistoScanning™) improves staging reliability of prostate biopsies

Objective

Imaging biomarkers like HistoScanning™ augment the informative value of ultrasound. Analogue image-guidance might improve the diagnostic accuracy of prostate biopsies and reduce misclassifications in preoperative staging and grading.

Results

Comparison of 77 image-guided versus 88 systematic prostate biopsies revealed that incorrect staging and Gleason misclassification occurs less frequently in image-guided than in systematic prostate biopsies. Systematic prostate biopsies (4–36 cores, median 12 cores) tended to detect predominantly unilateral tumors (39% sensitivity, 90.9% specificity, 17.5% negative and 50% positive predictive values). Bilateral tumors were diagnosed more frequently by image-guided prostate biopsies (87.9% sensitivity, 72.7% specificity, 50% negative and 96.8% positive predictive values). Regarding the detection of lesions with high Gleason scores ≥ 3 + 4, systematic prostate and image-guided biopsies yielded sensitivity and specificity rates of 66.7% vs 93.5%, 86% vs 64.5%, as well as negative and positive predictive values of 71.2% vs 87%, and 83.3% vs 79.6%, respectively. Potential reason for systematic prostate biopsies missing the correct laterality and the correct Gleason score was a mismatch between the biopsy template and the respective pathological cancer localization. This supports the need for improved detection techniques such as ultrasound imaging biomarkers and image-adapted biopsies.

[Indications and limits of ablative therapies in prostate cancer]

OBJECTIVE

To perform a state of the art about indications and limits of ablative therapies for localized prostate cancer.

METHODS

A review of the scientific literature was performed in Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of keywords. Publications obtained were selected based on methodology, language and relevance. After selection, 107 articles were analysed.

RESULTS

The objective to combine reduction of side effects and oncological control has induced recent development of several ablative therapies. Beyond this heterogeneity, some preferential indications appear: unilateral cancer of low risk (but with significant volume, excluding active surveillance) or intermediate risk (excluding majority of grade 4); treatment targeted the index lesion, by quarter or hemi-ablation, based on biopsy and mpMRI. In addition, indications must considered specific limits of each energy, such as gland volume and tumor localization.

CONCLUSION

Based on new imaging and biopsy, ablative therapies will probably increased its role in the future in management of localize prostate cancer. The multiple ongoing trials will certainly be helpful to better define their indications and limits.

Evaluation of Prostate HistoScanning as a Method for Targeted Biopsy in Routine Practice

BACKGROUND

Prostate HistoScanning (PHS) is a tissue characterization system used to enhance prostate cancer (PCa) detection via transrectal ultrasound imaging.

OBJECTIVE

To assess the impact of supplementing systematic transrectal biopsy with up to three PHS true targeting (TT) guided biopsies on the PCa detection rate and preclinical patient assessment.

DESIGN, SETTING, AND PARTICIPANTS

This was a prospective study involving a cohort of 611 consecutive patients referred for transrectal prostate biopsy following suspicion of PCa. PHS-TT guided cores were obtained from up to three PHS lesions of ≥0.5cm³ per prostate and only one core per single PHS lesion. Histological outcomes from a systematic extended 12-core biopsy (Bx) scheme and additional PHS-TT guided cores were compared.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Comparison of PHS results and histopathology was performed per sextant. The χ² and Mann-Whitney test were used to assess differences. Statistical significance was set at p<0.05.

RESULTS AND LIMITATIONS

PHS showed lesions of ≥0.5cm³ in 312 out of the 611 patients recruited. In this group, Bx detected PCa in 59% (185/312) and PHS-TT in 87% (270/312; p<0.001). The detection rate was 25% (944/3744 cores) for Bx and 68% (387/573 cores) for PHS-TT (p<0.001). Preclinical assessment was significantly better when using PHS-TT: Bx found 18.6% (58/312) and 8.3% (26/312), while PHS-TT found 42.3% (132/312) and 20.8% (65/312) of Gleason 7 and 8 cases, respectively (p<0.001). PHS-TT attributed Gleason score 6 to fewer patients (23.4%, 73/312) than Bx did (32.4%, 101/312; p=0.0021).

CONCLUSIONS

Patients with a suspicion of PCa may benefit from addition of a few PHS-TT cores to the standard Bx workflow.

PATIENT SUMMARY

Targeted biopsies of the prostate are proving to be equivalent to or better than standard systematic random sampling in many studies. Our study results support supplementing the standard schematic transrectal ultrasound-guided biopsy with a few guided cores harvested using the ultrasound-based prostate HistoScanning true targeting approach in cases for which multiparametric magnetic resonance imaging is not available.