Free Hand Transperineal Prostate Biopsy Offers Equivalent Cancer Detection and Improved Antibiotic Stewardship Compared to Transrectal Ultrasound-Guided Prostate Biopsy
Christian Schaufler, BS, Ryan Daigle, BS, Carl K. Gjertson, MD, Peter C. Albertsen, MD, Benjamin T. Ristau, MD.
University of Connecticut School of Medicine, Farmington, CT.
BACKGROUND: Transrectal ultrasound guided prostate biopsy (TRUS-B) is the gold standard for diagnosing prostate cancer. Due to the risk of infectious complications associated with TRUS-B, there has been increasing interest in transperineal prostate biopsy. We compared a prospectively collected cohort of freehand transperineal prostate biopsy (fTP-B) to an institutional cohort of TRUS-B patients. Differences in cancer detection and the amount of cancer within a given core were examined.
METHODS: A historical cohort of patients who received TRUS-B from January 2017 to September 2018 (n=170) was compared to a prospectively collected cohort of fTP-B patients (n=101) from February 2019 through January 2020. TRUS-B patients underwent a 10 or 12 core biopsy and fTP-B patients underwent a 20-core biopsy. All TRUS-B patients were treated with prophylactic antibiotics while fTP-B patients received no prophylaxis. Biopsy core length and percent of total core were determined from the surgical pathology report. Positive cancer was defined as grade group 1 or higher, while clinically significant cancer was defined as grade group 2 or higher. Cancer detection rates were compared using chi-squared tests, and core length and percentage of core length were compared using student's T tests. A p value of < 0.05 was considered statistically significant.
RESULTS: 271 patients were included (170 TRUS-B, 101 fTP-B). Men undergoing fTP-B were slightly older (Median 65.6y, IQR 59.9-79.6) than those undergoing TRUS-B (63y, IQR 58.0-69.0; p=.03). There were no significant differences in median prostate PSA before biopsy (TRUS-B 9.4 ng/mL, IQR 6.8-17.4 and fTP-B 9.4, IQR 6.7-13.4; p=0.82), PSA density (TRUS-B 0.36, IQR 0.16-0.38 and fTP-B 0.48, IQR 0.19-0.42, p=0.27), or race (p=0.52) between the cohorts. Clinically significant prostate cancer was more often diagnosed in men undergoing fTP-B (52/101, 51.5%) compared to TRUS-B (64/170, 37.6%; p=0.01). This difference was attenuated when a 12-core template for fTP-B was derived from the original 20-core template (47/101, 46.5%; p=0.15) Cancer core length was greater in TRUS-B (median 4.0mm, IQR 1.2-8.5) relative to fTP-B (median 2.8mm, IQR 1-6; p<.001). There was no difference between percentage core involvement with cancer between TRUS-B (median 40%, IQR 10-75) and fTP-B (median 30%, IQR 10-70, p=.06). There were no infections in the fTP-B group and 2 confirmed cases of UTI/sepsis in the TRUS-B group.
CONCLUSIONS: A 20 core fTP-B results in greater detection of clinically significant prostate cancer compared to 10-12 core TRUS-B. This difference was attenuated when biopsy techniques with similar core numbers were compared. Despite omission of antibiotics in all cases, there were no infections in the fTP-B group. While 2 cases of UTI/sepsis were confirmed in the TRUS-B group, accurate determination of the infection rate in TRUS-B was limited due to lack of adequate follow-up information. Further work in disseminating fTP-B should be explored since fTP-B offers at least equivalent cancer detection and enables superior antibiotic stewardship compared to TRUS-B.
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