Detection, localisation and characterisation of prostate cancer by prostate HistoScanning(™)

Abstract

What's known on the subject? and What does the study add? Prostate cancer is one of the few solid-organ cancers in which imaging is not used in the diagnostic process. Novel functional magnetic resonance imaging techniques offer promise but may not be cost-effective. Prostate HistoScanning(™) (PHS) is an ultrasound-based tissue characterisation technique that has previously shown encouraging results in the detection of clinically significant prostate cancer. The present study reports on the open 'unblinded' phase of a European multicentre study. The prospective 'blind' phase is currently in progress and will determine the value of PHS in a robust fashion overcoming many of the biases inherent in evaluating prostate imaging.

Objective: To evaluate the ability of prostate HistoScanning(™) (PHS) an ultrasound (US)-based tissue characterization application, to detect cancer foci by correlating results with detailed radical prostatectomy (RP) histology.

Patient and methods: In all, 31 patients with organ-confined prostate cancer, diagnosed on transrectal biopsies taken using US guidance, and scheduled for RP were recruited from six European centres. Before RP three-dimensional (3D) US raw data for PHS analysis was obtained. Histology by Bostwick Laboratories (London) examined sections obtained from whole mounted glands cut every 3-4 mm. Location and volume estimation of cancer foci by PHS were undertaken using two methods; a manual method and an embedded software tool. In this report we evaluate data obtained from a planned open study phase. The second phase of the study is 'blinded', and currently in progress.

Results: 31 patients were eligible for this phase. Three patients were excluded from analysis due to inadequate scan acquisition and pathology violations of the standard operating procedure. One patient withdrew from the study after 3D TRUS examination. PHS detected cancer ≥ 0.20 mL in 25/27 prostates (sensitivity 93%). In all, 23 patients had an index focus ≥ 0.5 mL at pathology, of which 21 were identified as ≥ 0.5 mL by PHS using the manual method (sensitivity 91%) and 19 were correctly identified as ≥ 0.5 mL by the embedded tool (sensitivity 83%). In 27 patients, histological analysis found 32 cancerous foci ≥ 0.2 mL, located in 97 of 162 sextants. After sextant analysis, PHS showed a 90% sensitivity and 72% specificity for the localisation of lesions ≥ 0.2 mL within a sextant.

Conclusions: PHS has the ability to identify and locate prostate cancer and consequently may aid in pre-treatment and pre-surgical planning. In men with a lesion identified, it has potential to enable improved targeting, allowing better risk stratification by obtaining more representative cores. However further verification from the results of the blinded phase of this study are awaited.