AUA 2019: Transperineal vs. Transrectal MRI/US Fusion for Prostate Cancer Detection

Chicago, IL ( Transrectal ultrasound-guided transrectal prostate biopsies have been the standard method of diagnosing prostate cancer for decades. Over the past 15 years, there have been increasing concerns related to prostate biopsy-associated sepsis following transrectal biopsy. A transperineal biopsy may decrease these infectious complications.

MRI/US fusion biopsies are increasingly used to undertake targeted biopsies. These may be performed either via a transrectal or transperineal approach. In this single-center study from Petah Tikva, Israel, which was presented as a moderated poster this morning at the American Urologic Association Annual Meeting, Dr. Margel and colleagues report the results of a non-inferiority randomized trial comparing the prostate cancer detection rates of these two approaches.

The authors recruited patients undergoing MRI/US fusion biopsy. Each patient underwent both transrectal and transperineal MRI/US fusion biopsy using the Navigo fusion system with randomization based on which approach was performed first. In each case, the index lesion was sampled 4-6 times. Further, during the transperineal biopsy, a systematic biopsy was performed. The authors defined non-inferiority using a margin of 10%.

76 patients were randomized within this trial. The median age was 68 years (IQR 67-72 years) and the median PSA was 8.9 (IQR 6.2-12.2). Prostate cancer was diagnosed in 45 of 76 patients (59%), with clinically significant disease (Gleason score ≥7) in 21 (47% of patients diagnosed with prostate cancer). Prostate cancer was detected in the index lesion more frequently using the transperineal approach (44, 58%) than the transrectal approach (33, 44%) with an absolute difference of 14% (90% CI 1.3-27%, p=0.037). Thus, the study affirmed the non-inferiority of the transperineal approach and suggested (based on a 90% confidence interval) the superiority of this approach.

Interestingly, the authors then examined the different diagnosis rate between the two approaches on the basis of tumor anatomic location. Transperineal biopsies were particularly superior in the diagnosis of prostate cancer in the apex (47 vs 31%, p=0.043) and anterior (54 vs 31%, p=0.04), despite the fact that all biopsy were MRI-informed fusion biopsies. In these locations, the transperineal biopsy also resulted in significantly longer core lengths, which increases the prognostic information available from the biopsy.

While this study has focused on differences in cancer detection between transperineal and transrectal prostate biopsies, the transperineal biopsy is also associated with significantly lower infectious complications, albeit with an increased risk of urinary retention1.

Presented by: David Margel, MD, Department of Urology, Rabin Medical Center, Petah Tikva, Israel
Co-authored by: Yaara Ber, Sivan Sela, Daniel Kedar, Jack Baniel, Rabin Medical Center, Petah Tikva, Isreal

Written by: Christopher J.D. Wallis, Urology Resident, University of Toronto, Twitter: @WallisCJD at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois

1. Skouteris VM, Crawford ED, Mouraviev V, et al. Transrectal Ultrasound-guided Versus Transperineal Mapping Prostate Biopsy: Complication Comparison. Reviews in urology 2018; 20(1): 19-25.