In the early 1990's when systematic biopsy of prostate using transrectal ultrasonography (TRUS) had just begun, there was enthusiasm for identifying abnormalities and obtaining appropriate samples. Since the occurrences of early small prostate cancer are increasing and identifying tumors using TRUS are somewhat subjective, the efficiency of the method in detecting and staging prostate cancer has decreased. (Ohori, et al. 2003) Instead, many physicians discuss about where and how many biopsy cores should be taken in order to improve the detection-rate of cancer. Clinicians have also focused on the pathological features of cancer in biopsy specimens that sometimes provide significant information to stage prostate cancer. (.
