Biopsy Prophylaxis, Technique, Complications, and Repeat Biopsies

Biopsy prophylaxis

The majority of prostate biopsies are performed with transrectal ultrasound (TRUS) guidance and tissue sampling, with only a small proportion being done via a transperineal approach. The bacterial colonization of the rectum with gram-negative organisms poses a significant and potentially devastating risk of infection and sepsis during TRUS biopsy. Rates of sepsis after prostate biopsy have been traditionally reported to be 1–3%.

Risk factors for postbiopsy sepsis include antibiotic therapy within the past 6 months, history of prostatitis, and, most importantly, noncompliance with biopsy antibiotic prophylaxis recommendations. Those men with chronic indwelling urethral catheters, neurogenic bladder with elevated postvoid residuals, and history of exposure to multidrug resistant organisms (e.g., hospital employee) also deserve special attention to minimize risk of infection.

The American Urological Association (AUA) recommends antibiotic prophylaxis for all men undergoing TRUS biopsy of the prostate. This recommendation is based on level-1 evidence from randomized clinical trials (RCTs). The best-practice statement was last updated on January 1, 2014. First line agents for prophylaxis include oral quinolones, trimethoprim-sulfamethoxazole (tmp-smx), and oral cephalosporins (first, second, and third generation). Alternative regimens include intravenous (IV)/intramuscular (IM) aminoglycosides or Aztreonam. The recommended duration of therapy is 24 h since several RCTs have demonstrated equivalent efficacy of 24-h dosing compared with 3-day regimens. These recommendations are for empiric therapy, assuming preprocedure urine cultures are negative. When organisms have been isolated from rectal swab cultures, antimicrobial therapy should be selected based in culture data. For those clinicians working in the hospital setting, it is prudent to review institutional data on organism susceptibilities to various antimicrobials. For example, the rate of quinolone- and tmp-smx-resistance may vary widely between and within institutions over time. Updated hospital sensitivity data should be consulted when selecting the best prophylaxis regimen.

Minimizing the risk of postbiopsy infection has been extensively investigated, and in additional to adhering to the previous recommendations, isolated studies have demonstrated adjunctive maneuvers to further decrease the rate of infection. The use of broad-spectrum IV antibiotics prior to biopsy has demonstrated a decreased rate of infection compared with standard oral regimens. In a prospective study ( n = 170), the incidence of sepsis after prostate biopsy was compared in men receiving IV ertapenem plus oral agents versus oral agents alone. The group receiving the additional IV ertapenem demonstrated a significantly decreased incidence of sepsis (0% vs. 6.7%, p = 0.03). The benefit of decreased sepsis rates with IV antibiotics must be weighed against the additional cost and inconvenience with this strategy.

Fluoroquinolone resistance rates over 20% have been demonstrated in the rectal carriage of men undergoing prostate biopsy. Indeed, rectal swab culture taken in advance of prostate biopsy is one strategy to minimize the risk of postprocedure infection. Taylor et al. compared targeted prophylaxis (culture swab data) and empiric prophylaxis in a study of 457 men and showed a significant decrease in infectious complications using the targeted approach. Importantly, the targeted therapy approach was significantly more cost-effective than empiric therapy due to the fact that managing infectious complications is extremely expensive. The use of betadine-impregnated enemas prior to biopsy has yielded decreased bacterial colony counts in the rectum as well as fewer infectious complications. Disinfection of the needle tip with formalin after each biopsy core taken has also shown a decreased risk of sepsis in a retrospective study.

The authors recommend following the Best Practice Guidelines of the AUA and tailoring prophylaxis choices to local institution bacterial sensitivities. If, after review of internal data, infection rates are still higher than expected (1–2%), then consider employing one or more of the previously mentioned strategies to minimize infection.

Historically, all antiplatelet and anticoagulant agents such as aspirin and warfarin were discontinued prior to prostate biopsy for fear of increased bleeding (hematuria, rectal bleeding). However, several recent studies show that continuing these medications does not increase the risk of postbiopsy hemorrhage. This finding is particularly important in patients with strong indications for antiplatelet agents (e.g., recent coronary stent) and anticoagulants (e.g., atrial fibrillation, embolic stroke). It is our recommendation to continue these agents prior to prostate biopsy for the majority of men, especially those with significant cardiovascular and cerebrovascular disease.

Biopsy technique and specimen processing

Prostate biopsy technique has dramatically evolved over the past several decades. The days of finger-guided biopsies in the preultrasound era and the classic 6-core “sextant” biopsy from the 1980s and 1990s have made way for the modern day 12-core prostate biopsy. Biopsy technique has continued to evolve with the goals of maximizing clinically significant cancer-detection rates (CDR), avoidance of false negative biopsies (better NPV), minimizing the identification of indolent cancers, providing good concordance with surgical specimen pathology to reliably assess risk and guide treatment options, and containing costs. The modern day TRUS-guided prostate biopsy can be described as a 12-core systematic sampling, including the far lateral and apical regions of the prostate. Newer techniques involving magnetic-resonance imaging (MRI)-guided biopsy and MRI–Ultrasound fusion biopsy are beyond the scope of this chapter but will be addressed elsewhere in this text.