Optimal method for measuring tumor extent in needle biopsy specimens to identify small-volume prostate cancer

Objectives To compare various methods for measuring tumor extent in prostate biopsy specimens to identify small-volume prostate cancer. Methods A total of 100 radical prostatectomy specimens were retrospectively analyzed. Receiver operating characteristic analysis was used to compare the abilities of prostate-specific antigen density, and four measures of tumor extent in prostate biopsy specimens – positive core number, greatest percentage of cancer in a single core, greatest length of cancer in cores and total length of cancer in cores – to identify small volume prostate cancer. Four definitions of insignificant cancer volume were used in this analysis: index and total tumor volume