SAN DIEGO, CA USA (UroToday.com) - A panel discussion during the plenary session of the AUA sought to define the optimal method for prostate needle biopsy (PNBx) sampling and collection.
The goals of the panel were to define an optimal method for PNBx that includes an adequate number of cores to provide diagnostic confidence and to balance the risk of detecting lethal cancer against the avoidance of detecting clinically insignificant cancer. The panel sought to define the optimal number of primary biopsy cores needed and the ideal locations for sampling. Increasing the number of cores collected improves concordance rates with prostate cancer grade seen at the time of prostatectomy. However, there is no utility in increasing the number of cores obtained beyond 10-12. The highest diagnostic yield is obtained from sampling of the apex and far laterally. Routine biopsy of the transition zone is not warranted.
With regard to the labeling of individual cores, more vials collected will lead to the identification of more cancer, but there was no association with individual core labeling and the accurate prediction of extracapsular extensions (ECE) or surgical margin status. The participants argue that there is no compelling evidence for a benefit to individual labeling, as it does not affect clinical management. They concluded by stating, “individual labeling of cores is reasonable but offers very limited clinical benefit.” Alternate methods for core reduction could also save money.
The participants then compared the number of cores collected and the number of cores per cassette with regard to cancer yield, based on national benchmarks. The yield of cancer is identical whether 1 or 3 cores are placed in a cassette (n=6000). In analysis of over 2 million vials, they demonstrated a strong correlation (Spearman’s coefficient 0.97) between positive cancer biopsy rate and the number of specimen vials/biopsies. The mean, national, positive biopsy rate is 40.3%, and centers of excellence should expect a similar rate of positive biopsies.
The participants discussed the challenges posed due to core fragmentation, which can make accurate tumor quantification difficult. There are no definitive guidelines on how to deal with discontinuous foci of cancer, and no guidelines define how much interfocal stroma is allowable. Placing multiple and/or fragmented cores per container/cassette can compromise cancer detection, grading, and quantification. Further study and consensus are warranted.
Finally, the participants highlighted another area for improvement. In the United States, approximately 1:1000 prostate biopsy specimens are inadvertently mixed, mislabeled, or switched. Inappropriate mixing of specimens can have devastating consequences to patients. Mislabeling and specimen switching are “never events,” and urologists should strive for zero errors.
Presented by Steven M. Schlossberg, MD, MBA, Samson W. Fine, MD, David G. Bostwick, MD, and Samir S. Taneja, MD at the American Urological Association (AUA) Annual Meeting - May 4 - 8, 2013 - San Diego Convention Center - San Diego, California USA
Reported for UroToday.com by Jeffrey J. Tomaszewski, MD