Impact of increased number of biopsies on the nature of prostate cancer identified

Purpose: Increasing the number of cores obtained at the time of transrectal ultrasound guided prostate biopsy has increased the number of cancers identified. However, there is increasing recognition that many men with prostate cancer may not benefit from early, aggressive intervention and that over detection of prostate cancer has resulted in over treatment. We determined the impact of the greater number of prostate biopsies on the nature of cancer identified. Materials and Methods: In the Cancer of the Prostate Strategic Urologic Research Endeavor database, a longitudinal disease registry of men with prostate cancer, we identified those men diagnosed between 1999 and 2002 with complete data on serum prostate specific antigen, Gleason score, clinical T stage, number of biopsies obtained and number involved with cancer. Results: We identified 4,072 men with 6 or more prostate biopsies obtained at initial diagnosis. Of the men 30%, 47% and 24% underwent 6, 7 to 11, and more than 12 biopsies, respectively. The number of biopsies correlated significantly with numerous sociodemographic and clinical variables including prostate specific antigen, comorbidities and income. There did not appear to be differences in disease characteristics as assessed by Kattan and Cancer of the Prostate Risk Assessment scores among men with a biopsy number between 6 and 17. In the subset of 1,548 men undergoing radical prostatectomy, no differences in biochemical-free survival were observed among the various biopsy groups at a median followup of 2.2 years. Conclusions: The increasing number of prostate biopsies obtained at diagnosis increases cancer detection but the impact on disease characteristics remains unclear. Our data suggest that the risk stratification of prostate cancers is independent of biopsy number (6 or greater) in a contemporary cohort of men.