Oncology Prostate Cancer
Figure 1: The TargetScan 3D Transrectal Ultrasound Biopsy System
Figure 3: TargetScan Transrectal Biopsy Guide System
The guide system measures the biplanar depth (from the apex seen on the alphabetical scale), the degrees of rotation (selected on the circular grid surrounding the probe) and the biopsy guide showing the angle of passage of the biopsy needle. Source: Envisioneering Medical Inc.
The system comprises a probe and dual plane localisation system on a lockable gantry and computer control system with Bluetooth™ printing support. Source: Envisioneering Medical Inc.
Figure 2: Screenshot of the Touch-screen Control System of the TargetScan
The choice of which biopsy technique to use at which time and with which patient should be weighed against risks and purpose. Transperineal techniques appear to have a higher retention risk of 3.3–10%. Although infection rates would be expected to be higher with the transrectal template technique compared with standard transrectal biopsies, this risk can be reduced significantly using disposable guides.17
Using the Targetscan® (Envisioneering Medical
Technologies, St Louis, MO, US) in a multicentre study of 220 patients over three years, Tunsel et al. reported only one case of severe urosepsis.18
Active surveillance for low-risk, low-volume prostate cancers is becoming an increasingly common and popular management option. The concern in this group is potential understaging or missing a focus/foci of aggressive or clinically significant cancer. Offering this group of men re-biopsy using a saturation technique, either immediately or later, may confirm disease suitable for surveillance. In a small study of on a cohort of 35 men, Boccon-Gibod showed that one-third of cases were suitable to continue active surveillance, with the remaining patients shown to have multifocal cancer or upgraded Gleason scores. These men were offered radical therapy.19
Screenshot shows the transverse (top right) and sagittal (top left) views of the prostate. The biopsy planning system is seen on the bottom right of the screen and the 3D schematic of the biopsy sites is seen on the bottom left. Source: Envisioneering Medical Inc.
Saturation biopsy in men with previous negative biopsies is probably the most common indication for the technique. Cancer detection rates of up to 43% have been reported in this high-risk population.14 While most authorities agree that saturation biopsies are the most useful approach in this patient group, controversy exists as to whether a transperineal template technique or a transrectal technique is best. Emiliozzi et al. compared the two techniques in a study of 107 men. The overall cancer detection rate was 40%, with 38% of men having transperineal biopsies versus 32% in the transrectal group showing cancer.15
In a larger study of 783 men,
Kakawami compared the two approaches, taking 26 cores overall: 12 transrectally and 14 transperineally. The overall cancer detection rate was 36%, with no difference between the techniques.16
20
The one warning about saturation biopsies is that, while they can improve cancer detection and staging information, the technique may overestimate Gleason scores and tumour volume in up to 10% of cases.11,20
3D Prostate Mapping
There is growing recognition that a ‘more is better’ approach to prostate biopsies does not necessarily increase cancer detection rates. The lack of reproducibility with respect to biopsy location is low with standard techniques. Accurate mapping or ‘painting’ the whole prostate gland with a template or 3D technique allows precision localisation and recording of cancerous or suspicious areas. These can then be re-sampled with much greater accuracy.
The TargetScan's rectal probe, incorporating a transrectal ultrasound transducer, is positioned on a fixed gantry that is locked into position after initial bi-planar scanning of the prostate in lithotomy position (see Figure 1).11,19
The rectal probe itself remains motionless after initial EUROPEAN UROLOGICAL REVIEW
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84