Sextant-Specific Analysis of Detection and Tumor Volume by HistoScanning™

Brachytherapy focal dose escalation using ultrasound based tissue characterization by patients with non-metastatic prostate cancer: Five-year results from single-center phase 2 trial

PURPOSE

This prospective trial investigates side effects and efficacy of focal dose escalation with brachytherapy for patients with prostate cancer.

METHODS AND MATERIALS

In the Phase II, monocentric prospective trial 101 patients with low-/intermediate- and high-risk prostate cancer were enrolled between 2011 and 2013. Patients received either PDR-/HDR-brachytherapy alone with 86-90 Gy (EQD2, α/β = 3 Gy) or PDR-/HDR-brachytherapy as boost after external beam radiation therapy up to a total dose of 91-96 Gy (EQD2, α/β = 3 Gy). Taking place brachytherapy all patients received the simultaneous integrated focal boost to the intra-prostatic tumor lesions visible in computer-aided ultrasonography (HistoScanning™) - up to a total dose of 108-119 Gy (EQD2, α/β = 3 Gy). The primary endpoint was toxicity. Secondary endpoints were cumulative freedom from local recurrence, PSA-free survival, distant metastases-free survival, and overall survival. This trial is registered with ClinicalTrials.gov, number NCT01409876.

RESULTS

Median follow-up was 65 months. Late toxicity was generally low with only four patients scoring urinary grade 3 toxicity (4/101, 4%). Occurrence of any grade of late rectal toxicities was very low. We did not register any grade ≥2 of late rectal toxicities. The cumulative 5 years local recurrence rate (LRR) for all patients was 1%. Five years- biochemical disease-free survival estimates according Kaplan-Meier were 98,1% and 81,3% for low-/intermediate-risk and high-risk patients, respectively. Five years metastases-free survival estimates according Kaplan-Meier were 98,0% and 83,3% for all patients, low-/intermediate-risk and high-risk patients, respectively.

CONCLUSIONS

The 5 years-results from this Phase II Trial show that focal dose escalation with computer-aided ultrasonography and brachytherapy for patients with non-metastatic prostate cancer is safe and effective.

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.