[Utility of prostate specific antigen doubling time in repeat biopsy for prostate cancer].

ABSTRACT

PURPOSE: It is not rare that the repeat biopsy is performed when the initial biopsy was negative. However, there is not a clear indication for the repeat biopsy. We evaluated the utility of prostate specific antigen doubling time (PSA-DT) as indication for the repeat biopsy. MATERIALS AND METHODS: Of men 103 underwent repeat biopsy after initial negative prostate biopsy, 55 men who had three or more serial PSA measurements until repeat biopsy were evaluated. PSA-DT was calculated using a log-linear regression model and compared with other PSA-related parameters. RESULTS: Prostate cancer was diagnosed in 22 patients (40.0%). Mean PSA-DT in 55 patients was 59.3 months. Comparing of repeat positive biopsy group and negative group, PSA density (PSAD) and PSA velocity (PSAV) in the positive biopsy group were significantly greater than in the negative biopsy group. Age, serum PSA concentration at initial and repeat biopsy, PSA adjusted for volume of transition zone (PSATZ), free to total PSA ratio (%F/T) did not recognize significant differences between both biopsy groups. PSA-DT of positive biopsy group (35.1 months) was significantly shorter than that of negative biopsy group (76.5 months). None was diagnosed prostate cancer whose PSA-DT was longer than 96 months. CONCLUSION: When we considered prostate repeat biopsy, it was thought that PSA-DT could be one important material, but it was limitation for indication as to other PSA-related parameters.