The importance of the transrectal ultrasound scan
No diagnostic of prostate is confirmed without a pathological examination of prostate biopsies. Through the years the manner prostatic biopsies have been taken has dramatically changed with a huge impact on the diagnostic accuracy. Initially digitally-guided the surge of the transrectal ultrasound scan (TRUS) has represented the first revolution in the field (picture 24). From a situation where the whole procedure was performed in a blinded manner with the TRUS the prostate became visible. The 80’s were the beginning of the ultrasound-guided or TRUS-guided biopsies with the use of a transrectal probe. At the same time in the biological field the PSA test became available allowing an earlier diagnosis and changing irreversibly the management of prostate cancer.
Picture 24 : A first milestone in the prostate imaging approach (Liddell HT et al. J. Urol. 1986)
Prostate biopsies are necessary in any man with a life expectancy of ten years or greater with an abnormal digital rectal examination (DRE) or an elevated PSA (usually above 4 ng/ml). In older men if the probability of an advanced or metastatic disease is high prostate biopsies may be needed before any palliative treatment.
• The technique
Except in very rare situations general anesthesia is not necessary and a local anesthesia is largely sufficient. They are different protocols for this procedure which takes place in the majority of the cases in an outpatient facility.
Picture 25 : Application of an enema few hours before the biospy procedure (by B. Batard)
Picture 26 : Antibioprophylaxia to reduce the risk of acute prostatitis – To take orally 1-2 hours or intravenously just before the biopsy
Picture 27a : Transrectal xylocaine injection (by B. Batard)
Picture 27b : Transperineal xylocaine injection (by B. Batard)
Picture 28 : Lateral decubitus position – only for transrectal biopsies
• Different sampling approach
Rapidly after starting to perform the biopsies by using the TRUS a standard mapping has been proposed on the base of six biopsies 3 in each lobe. After many studies have shown that this sampling was missing a certain proportion of cancer the so-called sextant biopsies scheme was proposed (pictures 29-30).
Picture 29 : 12 spots scheme applied without distinction amongst patients
Picture 31 : 3D prostate with unreached anterior lesion (in brown)
Picture 32 : High resolution targeted biopsy procedure based on a MRI/US fusion system
Picture 34 : Sagittal view of transperineal targeted biopsies (by B. Batard)
Picture 35 : Ginsburg protocol scheme (source : European Urology)