Prospective Randomized Multicenter Study Comparing Prostate Cancer Detection Rates of End-fire and Side-fire Transrectal Ultrasound Probe Configuration

Objective To prospectively test the hypothesis that end-fire transrectal ultrasound prostate biopsy probes have greater cancer detection rates than side-fire probes. Retrospective studies have suggested that such probes might have greater cancer detection rates. Methods The present prospective randomized multicenter trial aimed to compare the prostate cancer detection rates of the end-fire versus side-fire probe configuration during transrectal ultrasound-guided 12-core prostate biopsy. Patients were randomized according to age, prostate-specific antigen level and prostate volume. An interim analysis was planned after the inclusion of 300 patients. Results At the interim analysis after the inclusion of 297 patients, no differences were found in the mean prostate-specific antigen level ( P = .412), mean age ( P = .519), mean prostate volume ( P = .730), and positive digital rectal examination findings ( P = .295). The prostate cancer detection rate did not differ between the end-fire and side-fire probe (34.3% vs 34.4%, P = .972). On multivariate analysis, suspicious digital rectal examination findings (relative risk 8.185, P < .001), prostate-specific antigen level (relative risk 1.051, P = .041), and prostate volume (relative risk 0.973, P < .001), but not probe configuration (relative risk 0.942, P = .831), were independent predictive factors for the detection of prostate cancer. The interim analysis committee suggested that, because no difference of 5 absolute percent was achieved after 300 patients, no additional recruitment was necessary. Therefore, the study was terminated early. Conclusion The results of the present study have shown that the transrectal ultrasound probe configuration does not affect the prostate cancer detection rate during transrectal ultrasound-guided prostate biopsy.