Does the transrectal ultrasound probe influence prostate cancer detection in patients undergoing an extended prostate biopsy scheme? Results of a large retrospective study

OBJECTIVE To compare the prostate cancer detection rate and tolerance profile between a transrectal biopsy made with a 'side fire' (SF) and an 'end fire' (EF) ultrasound probe. PATIENTS AND METHODS We selected patients undergoing first biopsy and re-biopsy of the prostate with a 14- and 18-core template using EF and SF transrectal probes, respectively. We compared the cancer detection rate between the two probes on first biopsy and re-biopsy and gauged patient tolerance using a visual analogue scale (VAS). RESULTS A total of 1705 patients were included in the first biopsy group, while 487 were in the re-biopsy group. The overall detection rate of first biopsy was 37.2%; the overall detection rate of re-biopsy was 10.1%. No significant difference was found between the two probes in the first biopsy and re-biopsy sets (38% vs 36.5%, P = 0.55; 10.8% vs 9.3%, P = 0.7). The lack of any significant association between the type of probe used and prostate cancer detection was confirmed by univariable and multivariable analyses in both the first biopsy and re-biopsy sets after accounting for prostate-specific antigen values, per cent free prostate-specific antigen, digital rectal examination, and prostate and transition zone volumes. The patient tolerance profile of the SF group was significantly better than that of the EF group (mean VAS 1.78 +/- 2.01 vs 1.45 +/- 2.21; P = 0.02). CONCLUSION The prostate cancer detection rate does not depend on the type of probe used. However, the SF transrectal probe is associated with a better patient tolerance profile.