Transperineal vs. Transrectal MRI-targeted Prostate Biopsy

Prostate cancer is the most commonly diagnosed malignancy in U.S. men. There are approximately 1 million prostate biopsy performed annually in the U.S. Almost all biopsies are performed as an office based procedure in under 15 minutes. The precision of biopsy has improved over the last decade with the introduction of MRI guidance/targeting of suspicious lesions within the prostate.

However, significant limitations remain with this approach, including a significantly increasing risk of post-biopsy infection. This arises because more than 97% of all prostate biopsy are performed via a transrectal approach that introduces rectal bacteria with each pass of the biopsy needle into the sterile urinary tract. The current risk of post-transrectal biopsy infection, even with antimicrobial prophylaxis, is high at approximately 7% overall with 3% (30,000 men) requiring hospitalization annually.

Transperineal biopsy is an alternate approach that eliminates the direct introduction of bacteria from the rectum to the prostate. This approach, which is perfomed without antimicrobial prophylaxis, instead passes the biopsy needle through the perineal skin and pelvic floor.

Transperineal biopsy has not been widely adopted for several reasons. Historically, it has been considered too painful for patients in the clinic and thus was traditionally performed under general anesthesia. The added time, inconvenience and cost has limited its national adoptance. Second, when transrectal biopsy was initially adopted over 40 years ago, antibiotic resistance of rectal flora was not a challenge.

Beyond the potential for in-office transperineal biopsy to significantly reduce or eliminate biopsy infections, transperineal biopsy may also improve cancer detection: studies of transperineal biopsy (performed under general anesthesia) demonstrate higher detection rates for prostate cancer, particularly for anterior zone tumors, compared to transrectal biopsy. This is notable, as anterior tumors are difficult to sample with transrectal. Anterior tumors are also twice as likely to occur in African American men. In fact, our research demonstrates that some of the outcomes disparities in African American men may stem from an underdiagnosis of anterior prostate cancers.

Although transrectal biopsy is used widely, it is associated with a significant and increasing risk of biopsy infections due to growing antibiotic resistance, highlighting the urgent need for a safer alternative approach to prostate biopsy. The study investigators have refined a transperineal approach under local anesthesia with MRI-targeting/guidance without the need for antibiotic prophylaxis. The investigators hypothesize that transperineal MRI targeted biopsy will: (1) largely eliminate post-biopsy infections and costly hospitalizations for urosepsis; (2) be performed in the office with similar discomfort and non-infectious complications compared to transrectal MRI targeted biopsy; and (3) have significantly better detection of prostate cancer.

This multi-center randomized controlled trial will be conducted to evaluate in-office transperineal MRI targeted vs. transrectal MRI targeted biopsy, the current gold standard. This has transformative impact to change current standard of practice.