In our routine practice at University College London, we do not prescribe preoperative preparation, although minimal bowel preparation with a phosphate enema the night before or on the day of the procedure significantly improves ultrasound imaging of the prostate. An alpha-blocker such as tamsulosin or alfuzosin, although not essential, may be prescribed prior to the procedure (2–7 days). It is strongly recommended to prescribe a 2-week course of tamsulosin postoperatively in order to minimize the risk of acute urinary retention. Seven days prior to the procedure, antiplatelet agents should be stopped. Anticoagulants should be stopped after consultation with local guidelines.

The patient is positioned in the lithotomy position and a short-term urethral catheter is usually fitted. The catheter’s main function is to delineate the urethra as a landmark to help align the prostate on ultrasound imaging and also to avoid injuring the urethra especially if it is deviated from the midline in nonsymmetrically enlarged glands usually due to benign prostatic hyperplasia. The catheter is spigotted, and the bladder should not be emptied to allow the bladder neck to be visualized on ultrasound. The scrotum and penis are taped to the abdomen. A biplanar ultrasound probe covered with an endocavity balloon mounted on a brachytherapy stepper is introduced into the rectum to visualize the prostate (Fig. 8.3). While inflating the balloon with water, it is essential to make sure most or all air bubbles are removed to avoid image artifacts (Fig. 8.4).

After the probe is introduced, the midline reference plane is established by visualizing the urethra and the catheter at the center of the sagittal plane or at the midline on the transverse plain on real-time ultrasound. This should be equivalent to the capital letter “D” on the 5 mm biopsy grid on transverse (axial) view (Figs. 8.5 and 8.6).

It is important to ascertain that the posterior aspect of the prostate is included within the biopsy grid by moving the probe and stepper anteriorly or posteriorly and inflating/deflating the balloon (Fig. 8.6) to ensure adequate sampling of the peripheral zone specially at the level of the prostate base.

It is important to establish the position of the anterior aspect of the prostate in relation to the bony pubic arch to ascertain needle access to the anterior aspect of the prostate. Avoiding the pubic arch obstructing the needle path can be established by a combination of further extended hip flexion, balloon deflation, and stepper repositioning (Fig. 8.5).

Once an acceptable setup is achieved, the perineum is cleaned and the patient is draped. Shaving the perineum is optional. A sterile plastic drape and a brachytherapy type 5 mm sterile disposable grid are attached (Fig. 8.7) to the stepper. It is important that the template grid is calibrated to match the 5 mm grid seen on the ultrasound screen.

On sagittal view, the prostate should be divided visually to cranial (basal) and caudal (apical) halves provided the prostate is large enough. The basal and the apical portions will be biopsied and potted separately. To perform a full template mapping biopsy, the biopsy needles are deployed through the template grid once apically and then basally before moving on to the next coordinate (hole) on the grid (Fig. 8.8) while avoiding injuring the urethra and the bladder. To avoid the urethra the midline plane anteriorly is always spared from biopsy (Fig. 8.5), which is usually the anterior coordinates along the D line in the grid. After obtaining a sample the needle should be rinsed in chlorhexidine and then in sterile water before it is reloaded and passed back to the operator. To save time two needles should be used in every procedure to allow the operator to biopsy while the sample is obtained from the other needle and allowing for it to be prepared, and reloaded for use. Figure 8.9 shows the scrub nurse’s equipment setup. Once the whole gland is sampled, the catheter is removed and the patient can be discharged on the same day provided they are voiding urine well with no large residual volumes.

Biopsy cores can be labeled individually according to their X, Y coordinates on the grid and Z coordinates relating to whether it is basal or apical. The alternative is to divide the prostate into zones. There are also several ways to divide the prostate into anatomical zones. Barzell et al. initially divided the prostate into octants and then further divided them into three zones yielding 26 separate specimen pots [20]. Our group in University College London modified this further into the modified Barzell zones where the prostate is segmented into 20 zones (Fig. 8.10); then later reduced into 12 zones only to reduce the resource burden on pathology services (Fig. 8.11). The choice of approach should be driven first by the required accuracy of information and second by the amount of burden and logistics that can be tolerated. For example, if a TPM is used as a reference standard in a clinical trial validating a diagnostic modality like MRI as, for example, the PROMIS trial [25], a core-by-core coordinate record would yield the most accurate information at the expense of theater time, the need for logistical support, and histopathology processing cost. These issues can be mitigated using zonal sampling in which 5 mm sampling frequency is maintained but the cores geographically grouped and potted together. If the aim is for focal therapy, grouping the biopsies into zones should be sufficient to plan accurate treatment. In centers that only perform radical therapy, there is much less emphasis on the location of the disease and more on the risk stratification of the patient; hence, there will be no benefit in obtaining that level of detailed information.

With respect to morbidity and expected side effects, TPM biopsies have a similar side effect profile to that of TRUS-guided biopsy with three important differences. First, they carry a significantly lower risk of urosepsis (<0.5 %) – the most serious complication of TRUS-guided biopsy – as the needles do not traverse the rectal mucosa. Second, TPM biopsies confer a higher risk of self-limiting failure to void urine (5–10 %) as a result of greater gland swelling [26–28] compared to 1–2 % risk associated with TRUS-guided biopsy. Third, TPM biopsies require a general/spinal anesthetic, although in expert hands a limited mapping biopsy can be performed under sedation with local skin and periprostatic anesthesia [23]. On a more recent study by Losa et al. [29] comparing complication rates, according to the Clavien-Dindo classification, and changes in the quality of life, evaluated using the International Prostate Symptom Score, International Index of Erectile Function, and Functional Assessment of Cancer Therapy-Prostate questionnaires, before and 1 month after, template mapping biopsies did not appear to have a significant effect on the quality of life, and no life-threatening complications occurred, with negligible global Clavien-Dindo complication rates revealed.