Type of transrectal ultrasonography probe influences prostate cancer detection rates on repeat prostate biopsy.

UNLABELLED: It is known that the end-fire probe detects more prostate cancer on initial prostate biopsy, but there is no literature looking at the influence of type of probe on repeat biopsy. Given that the literature on the influence of ultrasonography probe on repeat prostate biopsy is non-existent, the present study adds information which may help urologists improve their chances of detecting prostate cancer on prostate biopsy. Determining which type of probe to use on a prostate biopsy is a simple external factor that may help improve patient management.

OBJECTIVE: To determine if the type of transrectal ultrasonography (TRUS) probe used during repeat prostate biopsy influences prostate cancer detection rates.

PATIENTS AND METHODS: We conducted a retrospective chart review of 680 men undergoing repeat prostate biopsy at our institution between 2000 and 2010. Patient mean (range) age was 64.2 (39-95) years. The median (range) prostate-specific antigen (PSA) level was 5.5 (0.37-33.8) ng/mL and median (range) free PSA was 17 (5-45) %. Patient age, PSA, prostate volume, number of biopsy cores, time interval between initial and repeat biopsy, digital rectal examination and pathological findings were all included in a multivariate logistic regression analysis.

RESULTS: The use of an end-fire probe on repeat biopsy significantly increased prostate cancer detection (odds ratio [OR] 1.59, 95% confidence interval [CI]: 1.03-2.46). The time interval between 1(st) and 2(nd) biopsy was also significant (OR 1.46, 95% CI: 1.11-1.09). On univariate analysis, white race (OR 0.66, 95% CI: 0.44-0.99), increasing prostate volume (OR 0.70, 95% CI: 0.55-0.89), and higher free PSA (OR 0.54, 95% CI: 0.34-0.84) were associated with a decreased risk of cancer. When evaluating the different permutations of using an end-fire or side-fire probe on initial or repeat biopsy, there was no difference in prostate cancer detection regardless of order of use of an end-fire or side-fire probe.

CONCLUSIONS: An end-fire probe is associated with improved prostate cancer detection rates on both initial and repeat biopsy. The order of probe use does not appear to matter.