Comparing transperineal and transrectal approaches with insights from Korean research
For men facing the possibility of prostate cancer, the diagnostic process often leads to a critical procedure: the prostate biopsy. This examination, which extracts tiny tissue samples from the walnut-sized prostate gland, provides the definitive evidence needed to diagnose cancer. For decades, the standard approach has involved inserting a needle through the rectal wall—a method known as transrectal biopsy. While effective, this technique carries a hidden danger: the risk of serious infection caused by introducing rectal bacteria into the prostate and bloodstream.
Now, a revolutionary approach is transforming prostate cancer diagnosis. The transperineal biopsy, which accesses the prostate through the skin of the perineum (the area between the scrotum and rectum), offers a safer alternative without compromising diagnostic accuracy. Recent research from Korea provides compelling evidence that this method not only reduces infection risks but may actually improve our ability to detect clinically significant cancers. This article explores the science behind both techniques and examines how a simple change in approach is making prostate cancer diagnosis safer and more accurate.
The transperineal approach reduces infection risk from 2-5% to near-zero while maintaining diagnostic accuracy.
The transrectal biopsy has been the workhorse of prostate diagnosis for decades. In this procedure, doctors insert an ultrasound probe into the rectum to visualize the prostate gland. A spring-loaded needle then passes through the rectal wall to collect tissue samples from specific areas of the prostate. The approach benefits from being relatively quick and familiar to urologists worldwide.
However, this method has a significant drawback: the needle must pass through the rectal wall, which naturally contains bacteria. Despite antibiotic prophylaxis, this introduces a risk of infection, including in some cases life-threatening sepsis. Studies indicate that infectious complications occur in 2-5% of transrectal biopsies, with the PLCO trial citing a rate of 7.8 infectious complications per 1,000 biopsies 1 . The growing problem of antibiotic resistance has further exacerbated this risk, making previously manageable infections more dangerous.
The transperineal approach takes a different anatomical route. Instead of passing through the rectum, the biopsy needle is inserted through the skin of the perineum, completely bypassing the rectal wall. This fundamental difference eliminates the primary source of infection in prostate biopsies—rectal bacteria.
While this technique isn't new, recent advancements have made it more practical for office settings under local anesthesia. Early transperineal biopsies often required general anesthesia and specialized equipment, but modern "freehand" techniques have simplified the procedure 6 . The most significant advantage of this approach is its dramatically lower infection rate. A study of 8,500 men undergoing transperineal biopsy found that only about 1.5% required post-operative hospitalization, with no cases of sepsis reported 1 .
| Characteristic | Transrectal Biopsy | Transperineal Biopsy |
|---|---|---|
| Access Route | Through rectal wall | Through perineal skin |
| Infection Risk | 2-5% 1 | Near-zero when performed without antibiotics 7 |
| Pain Level | Generally well-tolerated | Potentially higher, but manageable with anesthesia 8 |
| Anesthesia | Local typically sufficient | Local possible with modern techniques 6 |
| Procedure Time | Shorter 3 | Longer due to setup 3 |
| Anterior Tumor Access | Limited | Superior 5 |
| Learning Curve | Minimal for experienced urologists | Steeper 7 |
A pivotal Korean study conducted at Pusan National University Yangsan Hospital provided compelling evidence for the superiority of MRI-targeted biopsy methods 4 . The researchers designed a prospective investigation involving 76 patients with elevated PSA levels (below 10 ng/mL) who underwent both multiparametric MRI and subsequent prostate biopsy.
The study employed a sophisticated approach: all patients received both traditional 12-core transrectal ultrasound-guided biopsies (TRUS-Bx) and MRI-visual targeted biopsies (MRI-visual-Bx). In the MRI-targeted approach, radiologists first identified suspicious regions on multiparametric MRI scans, which urologists then targeted during the biopsy procedure using visual estimation to match MRI findings with real-time ultrasound images.
This methodological design allowed for a direct comparison of both techniques in the same patients, eliminating individual variation factors. The researchers took an average of 2.42 targeted cores per patient when suspicious lesions were identified on MRI, in addition to the standard 12 systematic cores. All samples were carefully analyzed by genitourinary pathologists who measured cancer core length, Gleason score, and other significant parameters.
76 patients with PSA <10 ng/mL
Both TRUS-Bx and MRI-visual-Bx performed
12 systematic cores + average 2.42 targeted cores
Genitourinary pathologists measured cancer parameters
The findings from this meticulous study revealed substantial differences in diagnostic capability between the two approaches. The MRI-visual targeted biopsy method demonstrated significantly superior performance in detecting clinically significant prostate cancer compared to the traditional transrectal approach.
Specifically, the overall cancer detection rates were similar between methods (34.2% for TRUS-Bx vs. 47.9% for MRI-visual-Bx in patients with abnormal MRI findings), but the quality of detection differed dramatically. When examining the biopsy cores individually, the positive rate was 8.4% (77 of 912 cores) for TRUS-Bx compared to 46.6% (54 of 116 cores) for MRI-visual-Bx—a statistically significant difference (p<0.001) 4 .
Even more importantly, the MRI-targeted approach was far better at identifying clinically significant cancers—those requiring treatment rather than active surveillance. The researchers defined clinical significance based on cancer length greater than 5 mm and/or Gleason grade greater than 3. By these criteria, 74.1% of positive cores in the MRI-targeted group represented clinically significant cancer, compared to only 35.1% in the traditional biopsy group 4 .
MRI-targeted biopsy showed significantly higher positive core rates
| Diagnostic Measure | TRUS-Bx (12-core) | MRI-visual-Bx | P-value |
|---|---|---|---|
| Overall Cancer Detection Rate | 34.2% (26/76) | 47.9% (23/48) | Not significant |
| Positive Core Rate | 8.4% (77/912 cores) | 46.6% (54/116 cores) | <0.001 |
| Clinically Significant Cancer Detection | 35.1% (27/77 cores) | 74.1% (40/54 cores) | <0.001 |
| Mean Cancer Core Length | 3.2 mm | 6.3 mm | <0.001 |
| Gleason Score ≥7 | Less frequent | More frequent (p=0.028) | 0.028 |
These findings demonstrate that the MRI-targeted approach not only finds more cancer but specifically identifies the clinically significant cancers that require treatment. This precision reduces the risk of both overtreating harmless cancers and missing dangerous ones.
One particularly notable advantage of the transperineal approach confirmed by this and other studies is its superior ability to sample the anterior prostate 5 . Anterior tumors—located toward the front of the prostate—have traditionally been challenging to detect with transrectal biopsies, as the needle must travel through the entire gland to reach these areas, often resulting in undersampling.
The transperineal route provides more direct access to these anterior regions. Recent research confirms this anatomical advantage, with one study reporting anterior tumor detection rates of 94.1% for transperineal biopsy versus only 43.1% for transrectal approach 6 . This represents a crucial diagnostic improvement, as anterior tumors may comprise up to 20% of all prostate cancers and are often more aggressive.
Essential equipment for modern prostate biopsy procedures
High-field (typically 3.0 Tesla) MRI machines capable of producing detailed images of the prostate gland. These scanners use T2-weighted imaging, diffusion-weighted imaging (DWI), and dynamic contrast enhancement to identify suspicious areas based on tissue density, cellularity, and vascular patterns 4 .
Advanced ultrasound equipment featuring specialized end-fire transducers that provide simultaneous axial and sagittal views of the prostate. This allows for precise needle guidance during both transrectal and transperineal approaches 6 .
18-gauge, 25-cm spring-loaded biopsy needles that efficiently capture tissue cores with minimal trauma. For transperineal approaches, longer needles may be required to reach the prostate through the perineum 4 .
For fusion biopsies, either software-based MRI/TRUS fusion platforms or cognitive fusion techniques are used. Software systems electronically overlay MRI images onto real-time ultrasound, while cognitive fusion relies on the operator's mental registration of the MRI findings with the ultrasound anatomy 2 4 .
Povidone-iodine or chlorhexidine solutions for skin preparation (transperineal) or rectal cleansing (transrectal). Studies show rectal antiseptics significantly reduce infection risk in transrectal biopsies 1 .
The evidence supporting transperineal prostate biopsy, particularly when combined with MRI targeting, continues to accumulate. The dramatically lower infection risk addresses one of the most serious complications of prostate biopsy, with some studies of transperineal approaches reporting no infections even when performed without antibiotic prophylaxis 1 . This advantage cannot be overstated in an era of growing antimicrobial resistance.
Despite these benefits, adoption of the transperineal approach has been gradual. Barriers include the longer procedure time, higher costs, and the need for additional training 3 . As one analysis noted, "The procedural time is shorter for transrectal than for transperineal biopsy" but "TR biopsy has a greater risk of infectious complications" 3 . The learning curve presents another challenge, as urologists familiar with the transrectal approach must develop new skills and spatial understanding 7 .
Nevertheless, professional guidelines are shifting. The European Association of Urology now recommends the transperineal approach due to its lower risk of infectious complications 1 . This guidance reflects the growing body of evidence that patient safety can be significantly improved without sacrificing diagnostic accuracy.
As techniques continue to evolve—with freehand approaches under local anesthesia making the procedure more accessible—the transperineal biopsy is poised to become the new standard of care 6 . This transition represents more than just a technical improvement; it signifies a fundamental shift toward patient-centered diagnostic approaches that prioritize both safety and accuracy in prostate cancer detection.
The Korean study highlighted in this article, along with other recent research, provides clinicians with the evidence needed to confidently recommend this approach to patients. As these methods become more widespread, men facing prostate biopsy can look forward to safer procedures and more precise diagnoses, ultimately leading to better-informed treatment decisions and improved outcomes.
Transperineal biopsy is currently in the early adoption phase with growing evidence supporting its benefits.
Near-zero infection rates compared to 2-5% with transrectal approach
Superior detection of anterior tumors (94.1% vs 43.1%)
Higher rates of clinically significant cancer identification
Safer procedure with comparable comfort levels