BERKELEY, CA (UroToday.com) - The main objective of our clinical study was to assess, in routine surgical practice, the effect of accurately tracking biopsy cores in the real 3D space of the prostate with real time visual feedbacks and quality control and to evaluate its impact on cancer detection rate.
The two populations in our clinical study were comparable in terms of time, age, clinical stage, prostatic volume, PSA (mean < 10ng/ml, screened population), number of biopsies, and criteria for biopsy. A single experienced operator had performed all biopsies, so our study analyzed precisely the effect of 3D TRUS on the detection rate of prostate cancer.
First, we have found a better distribution of sampling with respect to patient prostate anatomy. This wider sampling was distributed homogeneously and symmetrically in the 3D space of the prostate. The better sampling was due to the visualization of the metallic biopsy needle indwelling in the real volume of the prostate and monitoring of each biopsy core as a reality and not as a fictive representation of a cognitively, operator-dependent, effective mental distribution under the 2D TRUS plane. It registers accurately not only the proximal end of the needle tract, but the real direction, orientation, and trajectory of the entire tract in a reliable and reproducible manner.
Second, histologic information gained from 3D biopsies showed longer cancer core length than standard 2D TRUS biopsies. This results from the intention to oversample different areas of the prostate rather than to cluster all biopsies to posterolateral peripheral zones. Risk classification systems used nowadays are based on the number of positive cores or the proportion of a core involved with cancer, then a man with disease classified as low risk on standard biopsy may have that same disease classified as intermediate- or higher-risk disease on a 3D biopsy. This difference in risk stratification was also reported from biopsy approaches with a high sampling density, like transperineal template-guided biopsy. In fact, transperineal external grid templates could ensure a homogeneous distribution of biopsy cores but it necessitates an increased number of cores, hospitalization, and a narcosis. We believe that the 3D system ensures, in the same manner, better distribution, in an ambulatory care setting, without need for narcosis as in respect to our routine practice under 2D TRUS. It results in a drift towards higher risk classification, which is a limitation of the sampling 2D method.
Third, a current challenge in prostate cancer diagnosis is to identify patients who warrant definitive treatments. All prostate biopsy protocols must be manipulated to detect clinically significant cancer. Many studies have evaluated the detection rate of prostate cancer for various biopsy schemes, including the transperineal approach; few have investigated the detection of clinically significant cancers. Our data are even more encouraging when comparing clinically significant prostate cancer detection rates between the 2 cohorts, which prove that 3D biopsy had a higher sampling efficiency than the 2D TRUS technique.
Written by:
Aoun Fouad, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
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