Approximately 1 million prostate biopsies are performed annually in the United States. This volume is expected to increase due to greater adoption of active surveillance. Historically, prostate cancer is diagnosed with a transrectal prostate biopsy. The transrectal approach continues to comprise 97 percent of all prostate biopsies performed. With the transrectal approach, the biopsy needle passes (at least 12 times) from the “dirty” rectum into the sterile prostate. Antibiotics are given beforehand to prevent infection. However, due to increasing bacterial resistance, the risk of infection is increasing, with current rates approaching 7 percent. These infections may require hospitalization, and the risk of death due to biopsy infection is approximately 1 in 1,000.
We have refined a transperineal (through the skin between the scrotum and the rectum) approach to prostate biopsy under local anesthesia. Traditionally, transperineal prostate biopsy was performed under general anesthesia. The higher costs and inconvenience prevent widespread adoption. With our in-office transperineal biopsy technique, we also incorporate MRI-targeting, which has gained widespread acceptance due to high-level evidence demonstrating its superiority in cancer detection over ultrasound-guided biopsy. Because the biopsy needle traverses antiseptic prepped skin, transperineal MRI-targeted biopsy does not require prophylactic antibiotics. In pooling 251 in-office transperineal MRI-targeted biopsies from our collaborative sites, we have yet to experience an infectious complication. We propose to conduct a randomized trial to yield the highest level of evidence and demonstrate that transperineal MRI-targeted biopsy has fewer infections, similar pain/discomfort, and better cancer detection than the standard transrectal MRI-targeted biopsy.
We also believe that the transperineal MRI-targeted approach will improve prostate cancer detection. This is because the transperineal MRI-targeted biopsy needle trajectory has better sampling of the anterior prostate as compared to transrectal MRI-targeted biopsy, in which the biopsy needle travels from posterior to anterior. This course may miss the anterior prostate, particularly in men with prostatic enlargement. This is also important because African-American men are twice more likely to have anterior prostate cancers compared to white men. Earlier and better detection of these anterior tumors with transperineal MRI-targeted biopsy may help resolve the epidemiologic finding that African-American men have more aggressive prostate cancers at diagnosis and are more than twice as likely to die from prostate cancer.
Should our belief that transperineal MRI-targeted biopsy is better than transrectal MRI-targeted biopsy be proven true, this will transform the current standard of care. We believe that transperineal MRI-targeted biopsy will largely eliminate infections related to biopsy and obviate the need for prophylactic antibiotics. This has the public health benefit of better antibiotic stewardship that can slow bacterial resistance and decrease adverse reactions associated with antibiotic use. Furthermore, the adoption of transperineal MRI-targeted biopsy may improve prostate cancer outcomes for African-American men through earlier and more accurate diagnosis.
Because the overwhelming majority of biopsies are currently performed transrectally, our randomized trial is urgently needed. This evidence is necessary to convince patients, doctors, professional societies, and payers that future prostate biopsies should avoid the rectum completely to combat the currently growing risk of infections.
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