TREXIT: initial experience with transperineal prostate biopsy under local anesthesia in an outpatient setting in South East Asia.

Dear Editor,

Compared to transrectal prostate biopsy, transperineal (TP) prostate biopsy avoids rectal bacteria, and thus, significantly reduces the risk of sepsis. Previous studies have shown extremely low rates of infection following TP prostate biopsies.12 Traditionally, TP prostate biopsies have been performed in the operating theater under general or spinal anesthesia. However, the introduction of the PrecisionPoint Transperineal Access System (Perineologic, Cumberland, MD, USA) facilitates freehand TP prostate biopsies to be performed under local anesthesia (LA).12 In this study, we present our initial experience with TP prostate biopsy using the device under LA in an outpatient setting. This is the first report of TP prostate biopsy under LA in South East Asia.

This is an institutional review board-approved audit of patients who underwent TP prostate biopsy from September 2019 to June 2020 in Tan Tock Seng Hospital (Singapore). Patients with raised serum prostate-specific antigen (PSA) or abnormal digital rectal examination (DRE) were offered TP prostate biopsy. Patients were advised to undergo multiparametric magnetic resonance imaging (mpMRI) prostate prior to TP biopsy, as per the international guidelines.3 Patients with Prostate Imaging Reporting and Data System (PI-RADS) 3 to 5 lesions seen on mpMRI prostate proceeded with TP cognitive-targeted and systematic prostate biopsies.4 Those with no suspicious lesion on MRI prostate underwent systematic biopsies only. Written informed consent was obtained from all patients before biopsy. Patients were prescribed a single dose of oral cefuroxime 500 mg (Zinnat, Aspen Pharmacare Australia Pte Ltd., Canberra, Australia) on the morning of the prostate biopsy. All biopsies were performed or supervised by a single urologist (TWT). Procedural techniques are outlined in . Data of patients who underwent TP prostate biopsy were entered into our database. Clinically significant prostate cancer (csPCa) was defined as Gleason grade group ≥2 cancer.

Procedural techniques for LA freehand transperineal prostate biopsy using PrecisionPoint device. (a) The patient is placed in a modified lithotomy position, and the scrotum is held away from the perineum with adhesive tapes. (b) Iodine is used to clean the perineum prior to draping. The perineal skin is marked to demarcate the lateral boundaries of the prostate. One percent lignocaine was used to infiltrate the skin on both sides of the midline. (c) A spinal needle is advanced through the PrecisionPoint access guide under ultrasound visualization to inject 1% lignocaine around the perineal body and to the apex of the prostate on each side. (d) PrecisionPoint device is inserted through the skin and advanced into the perineum until the tip is visualized with the biplanar ultrasound. Cognitive-targeted biopsies are first performed in patients with MRI targets, and this is followed by systematic biopsies, which are taken as per the distribution recommended by the Ginsburg Study Group.6 LA: local anesthesia; MRI: magnetic resonance imaging.

During the study, 72 TP prostate biopsies under LA were performed. The median age of patients was 70 (range: 46–83) years. The median prostate volume was 42.2 (range: 11.2–368.7) ml and the median PSA was 8.3 (range: 0.7–411.0) ng ml−1. Sixty patients underwent mpMRI prostate before the prostate biopsy, and 26 patients had PI-RADS 3–5 lesions and underwent both cognitive-targeted and systematic prostate biopsies.

In patients who underwent systematic biopsies alone (n = 46), prostate cancer (PCa) was detected in 23 (50.0%) patients, of whom 16 (34.8%) had csPCa. This group of patients included four patients with suspicion of metastatic PCa that did not undergo mpMRI prostate, and the median PSA was 338.8 (range: 306.0–411.0) ng ml−1. All four patients were diagnosed with csPCa on TP systematic prostate biopsies.

Of the 26 patients who underwent both cognitive-targeted and systematic prostate biopsies, PCa was detected in 19 (73.1%) patients, and csPCa was detected in 15 (57.7%) patients. Of note is that two of these patients had negative systematic biopsies but were found to have csPCa only on their targeted biopsies. Twenty-one patients had one target lesion and five patients had two target lesions. The detection rate of PCa was 33.3%, 93.3%, and 100% for PI-RADS 3, 4, and 5 lesions, respectively. The detection rate of csPCa was 33.3%, 66.7%, and 75.0% for PI-RADS 3, 4, and 5 lesions, respectively.

None of the patients had urinary tract infection or sepsis after biopsy. Two patients had acute urinary retention requiring temporary urethral catheter insertion. One patient returned to the Emergency Department with gross hematuria. He was discharged on the same day without requiring any intervention.

The main advantage of TP prostate biopsy is the significant reduction in sepsis rates after the procedure. None of our patients had infection or admission with sepsis after their biopsies. Similar negligible rates of urinary sepsis after TP prostate biopsy have been reported by other centers.12 Loeb et al.5 reported higher risk of urinary retention with TP prostate biopsy compared to the traditional 12-core transrectal prostate biopsy. Of note, the reported higher risk of urinary retention was in those patients undergoing TP template mapping biopsies under general anesthesia. While more cores were taken during TP prostate biopsy in our study (median number of 24 cores), only two patients had urinary retention requiring temporary insertion of urethral catheter. Kum et al.1 also reported a similarly low rate of urinary retention after TP prostate biopsies.

Freehand TP prostate biopsy under LA is a well-tolerated office procedure, and none of our patients required sedation. With the PrecisionPoint device (Perineologic), only two skin punctures were required to obtain all the prostate biopsy cores. They were monitored in the clinic after the procedure by a trained nurse, and most were discharged within 4 h.

We found high cancer detection rates in our study and this may be due to two factors. First, the prostate is more thoroughly sampled as we took systematic biopsies following the Ginsburg protocol, with more cores taken compared to the traditional 12-core transrectal prostate biopsy.6 Second, TP prostate biopsy allows increased detection of anterior cancers, which tend to be missed in transrectal prostate biopsies.7 In our study, the majority of patients (83.3%) underwent mpMRI prostate before proceeding with TP prostate biopsy. Although only 26 patients underwent MRI-targeted biopsies in our study, the detection rate for csPCa is quite similar to our previous study, which utilized software fusion for transrectal MRI-targeted biopsies.8

There are several limitations in our study. First, we acknowledge that the sample size is small, but this is a report of our initial experience with the LA TP prostate biopsy. In addition, the COVID-19 pandemic which has affected Singapore since the late January 2020 has had a significant impact on our outpatient urological services with a significant reduction in prostate biopsy sessions. We expect the number of patients scheduled for LA TP prostate biopsy to increase in the coming months with the gradual resumption of urology outpatient services. Second, we did not formally compare our results with transrectal ultrasound (TRUS) prostate biopsies in our center. However, a previous audit of our TRUS prostate biopsies (unpublished) had found a sepsis rate of 2.0%, which is in line with the reported range of clinical infectious complications of 1%–17.5% reported in a review by Borghesi et al.9

In conclusion, TP prostate biopsy under LA is a safe, effective, and well-tolerated procedure. Thus, it is progressively replacing transrectal biopsies in our center.

AUTHOR CONTRIBUTIONS

AY, RS and TWT researched on the topic. AY wrote the first draft. AY and RS prepared all the figures. AY and TWT critically evaluated the findings in the paper. All authors read and approved the final manuscript.

COMPETING INTERESTS

All authors declare no competing interests.