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The 20-core prostate biopsy protocol--a new gold standard?
Ravery V, Dominique S, Panhard X, Toublanc M, Boccon-Gibod L, Boccon-Gibod L
Department of Urology, Bichat Hospital, Paris, France
J Urol. 2008; 179: 504-7

• 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.
  
  
• Editorial Comment
  The authors of this manuscript demonstrated that the 20-core biopsy scheme was more efficient for diagnosing prostate cancer than the 10-core biopsy scheme in 3 distinct subgroups of PSA levels .Unfortunately they did not evaluate these two different protocols according to the patient age and prostate volume. As we know, prostate volume is a relevant variable in the planning of the optimal number of cores in the first scheme of biopsy. In our experience, there is no magic number of cores to be taken that could be adequate for all patients. We think that the location from where these cores were taken is more important than the total number of cores. Several reports in the literature has been shown that for prostate less than 40 cc, a scheme with 12 cores is usually adequate. However, this scheme is usually inadequate for prostate larger than 80 cc. Another important issue to consider is whether additional cores are or are not routinely obtained from suspicious hypoechoic lesion or area with clear abnormal flow on color Doppler examination. In a review of 589 consecutive TRUS-guided biopsy , where we prospectively removed 12 cores from prostates < than 40 cc; 14 cores from prostates with 41-60 cc; 16 cores from prostates with 61-80 cc and 18 cores from prostates > than 80 cc), there was no proportional increase in the prostate cancer detection rate. The two best results were obtained with 12 cores/ < 40 cc (44.8%) and 16 cores/ 61-80 cc) = 36.5%. The detection rate obtained with the scheme with 18 cores/ > 80 cc was only 29%. Additional cores obtained in all patients from suspicious lesions on gray-scale and/or color-Doppler were not included in these results. The presence of suspicious hypoechoic was not statistically significant but the use of color Doppler increased the overall diagnosis rate in 8% of patients (isoechoic cancer). Color-Doppler ultrasound was particularly useful for the detection of cancer in patients with larger glands.

Dr. Adilson Prando
Chief, Department of Radiology and
Diagnostic Imaging
Vera Cruz Hospital
Campinas, São Paulo, Brazil
E-mail: aprando@mpc.com.br