Risk Factors and Predictors of Prostate Cancer in Men with Negative Repeat Saturation Biopsy.

INTRODUCTION: Despite evidence of increased cancer detection during repeat biopsy, no reports have addressed the likelihood of cancer detection after a negative repeat saturation biopsy or the risk factors that would warrant performing additional saturation biopsies. The investigators tested the hypothesis that a narrowly defined population with 2 biopsies showing no prostatic intraepithelial neoplasia (PIN) or atypia is effectively ruled out as having a risk of prostate cancer. METHODS: The authors retrospectively evaluated 655 patients that had repeat saturation prostate biopsies from April 2002 to January 2009. Repeat saturation biopsy included patients who had 2 or more biopsies with at least the most recent being a saturation biopsy of 20 cores or more. Repeat biopsy was performed if prostate-specific antigen (PSA) rose significantly after the last biopsy. The variables analyzed were PSA, age, race, number of previous biopsies, number of cores taken, inflammation on pathology specimens, total prostate volume, and digital rectal exam (DRE) results. RESULTS: Of the 655 patients with repeat saturation biopsies, 236 were truly negative, defined as no cancer, atypia, or PIN. In a mean follow-up of 33.2 months (range, 0-70) 70 of the 236 patients (30%) clinically required a repeat saturation biopsy. Of these, 10 (4.2%) developed prostate cancer. Most patients who were diagnosed with cancer had a PSA \u3e10 ng/mL at the first saturation biopsy, as opposed to PSA \u3c10 in the group that did not develop prostate cancer. In a multivariate analysis comparing patients that developed prostate cancer with those that remained cancer free, significant predictors of future prostate cancer were: higher number of previous biopsies (P = .006), higher number of cores taken (P = .02), decreased total prostate volume (P = .03), and change in PSA (P = .0002). PSA at first saturation biopsy (P = .006) and PSA at final follow-up evaluation (P = .0001) were significantly different between patients with and without prostate cancer. CONCLUSION: Patients with a history of negative saturation biopsy have around a 4% chance of being diagnosed with prostate cancer over a mean follow-up period of 33 months. Biopsy detection of prostate cancer in those men who had an additional biopsy because of elevated PSA or change in DRE resulted in a detection rate of 14%, which is clinically substantial. Patients with a rising PSA may warrant a lower threshold for subsequent repeat saturation biopsy. Saturation biopsy as repeat biopsy detects almost all significant cancers and may obviate the need for future biopsy in men who are carefully followed with clinical examinations