A prostate biopsy is a medical procedure used to collect small samples of tissue from the prostate gland to check for the presence of cancer. This diagnostic step is typically performed after initial screening tests, such as a prostate-specific antigen (PSA) blood test or a digital rectal exam, suggest a potential issue. Prostate cancer detection relies on accurate sampling of suspicious areas for laboratory analysis. Historically, one standard method dominated, but advancements in imaging and infection control introduced a distinctly different approach. The choice between the traditional transrectal method and the increasingly adopted transperineal method involves weighing procedural technique, associated risks, and patient recovery.
The Transrectal Approach
The transrectal ultrasound (TRUS) guided biopsy has long been the conventional method for obtaining prostate tissue samples. This technique involves inserting an ultrasound probe into the rectum to visualize the prostate gland. The urologist then guides a spring-loaded biopsy needle through the wall of the rectum and into the prostate to collect the tissue cores.
This approach became the standard because it offers relatively easy access to the prostate, particularly the posterior and lateral zones where many cancers develop. The procedure is typically performed in an outpatient setting using a local anesthetic. A periprostatic nerve block, involving injecting a numbing agent like lidocaine around the prostate, is commonly used to manage discomfort.
The simplicity and speed of the transrectal method allowed it to become widely adopted. However, the direct passage of the needle through the bacteria-containing rectal wall introduces a pathway for microbes to enter the prostate and the bloodstream. This is the primary reason for the infectious complications associated with this technique.
The Transperineal Approach
The transperineal biopsy (TPB) utilizes a different entry point, passing the needle through the skin of the perineum (the area between the scrotum and the anus). An ultrasound probe is still placed in the rectum to guide the procedure, but the needle punctures only clean, antiseptically prepared skin, rather than the bacteria-rich rectal mucosa. This method is increasingly favored because it isolates the needle path from the gastrointestinal tract, significantly reducing contamination.
Performing the transperineal technique often requires specialized equipment, such as a stepper or a brachytherapy grid, to precisely guide the needle to specific locations within the prostate. Since the perineal skin is more sensitive than the rectal wall, the procedure is often performed under deeper sedation or general anesthesia, though local anesthesia is sometimes used. The ability to access all regions of the prostate from this route makes it particularly well-suited for targeted biopsies.
Targeted sampling is frequently achieved by fusing pre-procedure magnetic resonance imaging (MRI) scans with real-time ultrasound images, known as MRI-fusion guidance. This technology allows the urologist to precisely aim the needle at small, suspicious lesions identified on the MRI. The transperineal route ensures that these targeted samples are collected accurately, even from the anterior or apical regions of the gland that may be difficult to reach via the transrectal route.
Comparison of Primary Risks
The most substantial difference between the two methods lies in the risk of serious post-procedure infection, particularly sepsis. The transrectal approach requires passing the needle through the rectal wall, introducing fecal bacteria into the prostate tissue. This direct inoculation results in a higher rate of post-biopsy infection, including the risk of severe sepsis requiring hospitalization.
Studies have shown that the rate of readmission for sepsis is significantly lower with the transperineal approach. For example, some data indicates a rate of readmission for sepsis after transrectal biopsy to be about 1.4%, which is measurably higher than the 1.0% observed after a transperineal biopsy in a large national audit. This disparity has led some major urological associations, such as the European Association of Urology (EAU), to recommend the transperineal route to reduce the reliance on prophylactic antibiotics and mitigate the risk of infection.
Regarding non-infectious complications, the transrectal method carries a higher risk of rectal bleeding because the puncture site is more vascular. Conversely, the transperineal method exhibits a much lower incidence of this complication. The risk of hematuria (blood in the urine) is generally not significantly different between the two procedures. The transperineal technique’s avoidance of the bacteria-rich rectal lumen provides a clear safety advantage concerning infectious adverse events.
Recovery and Patient Experience
Patient experience and expected recovery time differ between the two techniques. While the transrectal approach historically resulted in higher patient-reported pain scores during the procedure, recovery for uncomplicated transrectal biopsies is often very quick. Patients typically resume normal activities within one to two days with minimal lasting discomfort.
The transperineal approach, due to the injection of local anesthesia and potential swelling in the perineal area, sometimes results in a higher incidence of temporary urinary retention. This complication occurs when the patient cannot completely empty their bladder, occasionally requiring a short-term catheterization. One study found the post-biopsy urinary retention rate was significantly higher in the transperineal group (1.9% readmission rate) compared to the transrectal group (1.0%).
The higher rate of urinary retention with the transperineal method may also contribute to a greater likelihood of an overnight hospital stay in some settings. Despite this, the overall patient-reported experience for the transperineal procedure is often considered comparable or better because of the significantly reduced risk of a severe infection. Patients must balance the possibility of a brief period of urinary difficulty against the decreased risk of a potentially serious infection that could necessitate prolonged hospitalization.