IMAGING

Prostate biopsy: indications and technique
Matlaga BR, Eskew LA, McCullough DL
From the Department of Urology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
J Urol. 2003:169:12-19

• Purpose: The last decade has seen numerous modifications in the way prostate cancer is diagnosed. We review the current indications for and methods of prostate biopsy.
• Materials and Methods: The English language literature was reviewed regarding major indications for and methods of prostate biopsy. Pertinent peer reviewed articles were collated and analyzed.
• Results: The most widely accepted indication for prostate biopsy is a prostate specific antigen (PSA) value of greater than 4.0 ng./ml. However, some investigators advocate prostate biopsy for men with a PSA value in the 2.5 to 4.0 ng./ml. range, believing that use of this parameter results in detection of a greater number of cases of curable disease. Age specific PSA range, percent free PSA and presence of prostatic intraepithelial neoplasia or atypia are all considered to be relative indications for prostate biopsy. The current literature describes a trend toward increasing the number of cores obtained and the sites biopsied beyond those of the standard sextant technique. The additional cores in many series are obtained from more lateral regions of the gland.
• Conclusions: Although several criteria are used as indications for initial prostate biopsy, all are based on PSA level and/or abnormal digital rectal examination. Future improvements in currently used prostate cancer markers may result in better selection of cases to biopsy. There is no universally accepted technique of prostate gland biopsy. The current literature supports use of more extensive biopsy techniques to increase the likelihood of prostate cancer detection.
  
  
• Editorial Comment
  In the recent years, much has been written about how to optimize the indications and the techniques of transrectal ultrasound-guided biopsy for the detection of prostate cancer. This important compilatory study, nicely answered the most common questions about prostate biopsy, such as the following questions listed below: 1)- Decrease or not the PSA cutoffs to enhance prostate detection? To biopsy a patient with PSA of 2.5 to 4.0 ng/mL, would be advisable only in patients with family history, increased age-adjusted PSA, or abnormal digital rectal examination. 2)- Is intrarectal lidocaine jelly a good choice for local anesthesia? No, local anesthesia (periprostatic nerve block with 1% lidocaine) is far superior than that achieved with intrarectal lidocaine jelly. 3)- How many cores do we have to take during the biopsy? Although there is no consensus about the name of the approach of taking a larger number of cores from the far lateral portions of peripheral zone, it is clear that at least 12-13 cores are necessary. Interesting enough is that this number of cores has the same accuracy as the recent and invasive method called “saturation technique”. This saturation technique has the drawback of requiring a general anesthesia. 4)- Can we use endorectal magnetic resonance (MR) to improve the prostate biopsy accuracy? Yes, The overall accuracy of endorectal MR imaging to improve prostate cancer detection rate was 70%. So the finding of an abnormal area of hypo-intensity in T2-weighted images for a patient with previous negative biopsy is very suspicious and should be biopsied accordingly. 5)- Do we need to biopsy the transition zones routinely? No, there is not enough data to support this approach. The transition zones should be biopsied only in patients with previous negative biopsy, and in those with negative DRE and elevated PSA levels (>15 ng/mL).
  Unfortunately the authors did not mention the utility of color-Doppler ultrasound, particularly “power Doppler with echo-contrast”, which has been shown to be a useful method detecting 8-16 % of isoechoic neoplasms (1,2). This is particularly useful in patients with large prostates. The use of the 5 regions technique (13 cores) in patients with different gland sizes showed that the cancer detection rate was 43%, 27%, and 24% of men with prostate volumes <30 cc, 30 to 50 cc and >50 cc, respectively (3).Color Doppler ultrasound would certainly increase the cancer detection rate in this group of patients.

References
1. Prando A: The value of color Doppler in transrectal biopsy of the prostate. Radiol Bras, 30: 233,1997 [in Portuguese].
2. Lavoipierre AM, Snow RM, Frydenberg M, Gunter D, Reisner G, Royce PL, et al.: Prostatic cancer: role of color Doppler imaging in transrectal sonography. AJR Am J Roentgenol. 1998; 171:205-10.
3. Levine MA, Ittman M, Melamed J, Lepor H: Two consecutive sets of transrectal ultrasound guided sextant biopsies of the prostate for the detection of prostate cancer. J Urol. 1998;159:471-5.

Dr. Adilson Prando
Department of Radiology
Vera Cruz Hospital
Campinas, São Paulo, Brazil