Predictors of prostate cancer on repeat transrectal ultrasound-guided systematic prostate biopsy

Background: We analyzed the outcome of repeated transrectal ultrasound (TRUS)-guided systematic prostate biopsy in Japanese men whose clinical findings were suspected of prostate cancer after previous negative biopsies. Methods: Between January 1993 and March 2002, 1045 patients underwent TRUS-guided prostate biopsy. Among them, 104 patients underwent repeat biopsy due to indications of persistent elevated serum prostate-specific antigen (PSA), abnormal digital rectal examination (DRE) or TRUS, increased PSA velocity, and/or previous suspicious biopsy findings. Several clinicopathological factors were evaluated for their ability to predict the detection of prostate cancer on repeat biopsy. Results: Prostate cancer was detected in 22 of 104 patients (21.2%) who underwent repeat biopsies. PSA concentration and PSA density at both the initial and repeat biopsies, and PSA velocity in men with positive repeat biopsy were significantly greater than those in men with negative repeat biopsy. The incidence of abnormal findings in DRE and TRUS at initial biopsy in men with positive repeat biopsy was also significantly higher than that in men with negative repeat biopsy. However, neither the presence of prostatic intraepithelial neoplasia nor number of biopsy cores at initial biopsy had a significant association with the results of the repeat biopsy. Furthermore, multivariate analysis revealed that PSA and PSA density at both the initial and repeat biopsies, PSA velocity, and DRE and TRUS findings at initial biopsy were independent predictors of malignant disease on repeat biopsy. Conclusion: Despite an initial negative biopsy, repeat TRUS-guided biopsy should be carried out to exclude prostate cancer in cases of suspicious clinical findings, such as elevated PSA or PSA-related parameters, or abnormal findings of DRE or TRUS.