Frequently Asked Questions in Urology: Prostate Biopsy

Selected by Pietro Cazzola

 

Prostate cancerQuestion: What are the recommendations for follow-up when the pathology report shows High Grade Prostatic Intraepithelial Neoplasia (HGPIN) 

Answer: When HGPIN is diagnosed on prostate biopsy, in the absence of “atypia”, “ASAP” or actual prostate cancer, the follow-up differs depending on the amount of HGPIN that is seen. On a biopsy where “unifocal” HGPIN is seen (1 core) our pathology reports suggest repeat PSA and examination testing on a yearly basis and consideration of repeat biopsy in three years is suggested. However, when “extensive” HGPIN is reported (>2 cores) repeat biopsy is suggested sooner (6 months to a year).  The actual wording of such a pathology report is included below. 
“The median risk recorded in the literature for cancer following the diagnosis of HGPIN on needle biopsy is 24.1%, which is not much higher than the risk reported in the literature for a repeat biopsy following a benign diagnosis. The majority of publications which have examined in the same study the risk of cancer following a needle biopsy diagnosis of HGPIN to the risk of cancer following a benign diagnosis on needle biopsy have shown no differences between the two groups. Clinical parameters do not help in stratifying which men with HGPIN are at increased risk of being diagnosed with cancer. It is recommended that men do not need a routine repeat needle biopsy within the first year following the diagnosis of unifocal HGPIN on extended biopsy. It may be reasonable to perform a repeat biopsy three years following an initial HGPIN diagnosis on needle biopsy as a result of the uncertainty as to the long-term significance of this finding. [Journal of Urology (March) 175:820-34, 2006 and Journal of Urology (January) 175:121-4, 2006.]” 

Question: How does the pathologist determine the difference between atypical cells and prostate cancer when only a small amount of tissue is abnormal? 

Answer: Pathologists can add additional immunohistochemical stains to the biopsy material to look for basal cells (flat epithelial cells that lie beneath and outline the glandular secretory epithelial cells) – an example of such a report from pathology is below. 
“The diagnosis of carcinoma is supported by the failure of immunoperoxidase staining for high molecular weight cytokeratin and P63 to demonstrate basal cells in the atypical glands. Also favoring the diagnosis of cancer is that stains for RACEMASE (a marker preferentially expressed in prostate cancer) are positive.” 

Question: What are your absolute biopsy criteria for selection of men for an Active surveillance protocol? 

Answer: The biopsy criteria for selection of men for our Active Surveillance protocol include:

  1. No more than two cores positive for cancer
  2. No core with cancer with >50% involvement.
  3. No core with Gleason score >6 

Note: Unifocal Peri-neural Invasion (PNI) IS acceptable.  We also consider a PSA Density (PSAD) of <0.15 and stage T1c to be of great importance. 

Question: How many cores do you take on a routine biopsy, on an Active Surveillance biopsy and when you are repeating a biopsy for “atypia”? 

Answer: On a routine biopsy I take 12 cores with special attention to lateral placement of at least one core per area. On an Active Surveillance biopsy I take 14 cores (same 12 as above) with two additional cores taken for the Transition Zone.  When performing a re-biopsy for atypia, I take the original 12 areas and add 2-3 cores within the region of the atypia.  It should be noted that any palpable (T2-T3) or image suggestive (hypoechoic) area be sampled as well regardless of the biopsy indication. 

Question: What precautions do you take to limit the chance of post-biopsy sepsis? 

Answer: Studies from our institution and elsewhere have shown that antibiotic resistant E.coli strains are present in as much as 20% of the men presenting for biopsy. To predict this resistance and the need for a different or additional antibiotic we do rectal swabs on all men prior to prostate biopsy. The swab looks for fluroquinolone resistance. If no resistant strains are noted, the men get Ciprofloxacin 500 mg. 2 hours prior to the biopsy and 500 mg. every 12 hours after for two doses.  If resistant strains are seen, the lab does antibiotic resistance panels to suggest alternative antibiotics (e.g. Bactrim, Cephalosporin, Gentamicin, etc.).

Alan W Partin