The 20-core prostate biopsy protocol--a new gold standard?

ABSTRACT

PURPOSE: We investigated the ability of a 20-core prostate biopsy protocol to enhance the prostate cancer diagnosis rate. MATERIALS AND METHODS: We compared the diagnosis rate of prostate biopsies in 2 groups of consecutive patients, including group 1-10 cores and group 2-20 cores. The prostate specific antigen range in the 2 groups was 3 to 30 ng/ml and biopsies were performed because of increased prostate specific antigen (more than 3 ng/ml) and/or abnormal digital rectal examination. To analyze the results we divided each group into 3 subgroups according to prostate specific antigen, including group 1-3 to less than 6 ng/ml, group 2-6 or greater to less than 10 ng/ml and group 3-10 or greater to up to 30 ng/ml. Multivariate analysis was performed to assess the difference in the diagnosis rate among the subgroups according to the number of cores taken. RESULTS: The percent of positive biopsies was 39.7% in group 1 and 51.7% in group 2. Multivariate analysis confirmed that the number of biopsies taken was a factor that independently and significantly correlated with the prostate cancer diagnosis. The 20-core biopsy protocol was more efficient than the 10-core protocol in the 3 subgroups with 47.2% vs 28.1% of patients diagnosed in group 1 (OR 3.26, p = 0.001), 40.5% vs 36.1% in group 2 (OR 2.37, p = 0.009) and 69.8% vs 39.7% in group 3 (OR 2.01, p = 0.015). CONCLUSIONS: The 20-core biopsy protocol was more efficient than the 10-core biopsy protocol, especially in patients with prostate specific antigen between 3 and 6 ng/ml. Nevertheless, it is mandatory to confirm whether detected tumors are clinically significant on pathological examination of the radical prostatectomy specimens.