A midline lesion may be missed by random biopsy, since a biopsy is commonly not taken from midline tissue. However, cancer can be found over the midline (Fig. 6). Biopsy of the midline, especially at the apex, is delicate because the biopsy needle may penetrate the urethra in a sagittal plane biopsy. In this setting, biopsy can be performed in transverse view and the biopsy needle can be obliquely inserted in the midline apical nodule in order to prevent urethral injury (Fig. 7). The same strategy can be used for anterior midline lesion found on TRUS or MRI. Again, biopsy of the anterior midline lesion in sagittal view requires the needle to penetrate the urethral lumen. In order to avoid urethral injury, biopsy should be done in transverse view to avoid the needle entering into the urethral lumen (Fig. 8).

Biochemical failure with detectable PSA after radical prostatectomy can be seen in 30–40 % of cases in follow-up. Patients with a slow PSA rise and evidence of a positive surgical margin at the time of radical prostatectomy are more likely to have local recurrence. Biopsy in this setting is not generally considered mandatory prior to radiation therapy. However, confirmation of pathology and fiduciary marker placement may help to improve outcome.

Patients that have undergone abdominoperineal resection of the rectum (APR) have no access to the rectum. Digital rectal examination or transrectal ultrasonography cannot be performed, and often prostate cancer diagnosis can be delayed. PSA is the only tool for screening prostate cancer in this population. Transperineal ultrasound-guided prostate biopsy can be performed [16]. Generally, the procedure is performed with the patient in the left lateral decubitus position as in a regular TRUS procedure. In order to visualize the urethra and bladder clearly, placement of Foley catheter in advance is recommended. Intra-prostatic information is very difficult to obtain by transperineal ultrasound. The more important task of ultrasound in this procedure is localization and delineation of the prostate itself. For this purpose, an end-fire probe with a lower frequency setting, 5–6 MHz, is ideal for scanning, since better penetration and visualization of deeper tissue is required. After preparation of the skin with antiseptic solution, a probe is applied on the previous anus location that is frequently identifiable by a small skin dimple. Once the Foley catheter is identified, follow the catheter to identify the balloon. At this point, the prostate is seen next to the balloon. The prostate can be visualized either in a longitudinal or cross-sectional image (Figs. 19 and 20). Local anesthesia is given to the perineal skin, pelvic floor, and all the way to the prostate gland by ultrasound guidance. Care must be paid not to inject air during anesthesia, since this will significantly disturb the visualization of the prostate gland. Prostate biopsy can be done either with a sagittal or coronal view. The needle is advanced until it reaches the prostate capsule, as confirmed by ultrasound and a tactile sensation. After the needle tip reaches the prostatic capsule, the biopsy specimen is taken. Extended sextant biopsy of 12 samples can be obtained. Seminal vesicles are frequently biopsied as a staging purpose whenever it is visible, since the local staging cannot be performed by either digital rectal examination or transrectal ultrasonography. For a patient with severe anal stricture due to previous surgery or sphincter spasm, the TRUS probe can be applied over the anus and local anesthesia applied to the perianal tissue anterior to the anus. The prostate gland can be visible in this position and biopsy can be done as in the post-APR patient (Fig. 21).