By: Dan Sperling, MD

A multi-institute study offers sobering news for patients considering a conventional transrectal ultrasound (TRUS) guided prostate biopsy. A very large scale study co-authored by researchers from Mayo Clinic, Yale University School of Medicine, Case Western University/Urology Institute and two other research organizations concludes that while the absolute number of prostate biopsies is down, the rates of side effects have risen.[i]

The research team analyzed data from over 100,000 men who underwent prostate biopsies from 2005-14. The intent of the study was to explore the impact of major recommendations, guidelines and published studies against broad PSA screening on the rates of biopsy and post-biopsy complications. Data was taken from administrative healthcare coverage claims of 5,279,315 commercially insured men ages 40 and above, of whom 104,584 had prostate biopsies.

The study authors identified the following as possible influences on biopsy rates:

• The 2008 and 2012 US Preventive Services Task Force (USPSTF) recommendations
• The 2009 European Randomized Study of Screening for Prostate Cancer and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial
• The 2013 American Urological Association (AUA) guidelines

The team found that during the period of study, biopsy rates diminished by 33%, with immediate reductions after the 2008 and 2012 USPSTF recommendations and the 2013 AUA guidelines. Because the number of biopsies dropped, the absolute rate of complications decreased during the same period by 10%. “However, the proportion of men undergoing biopsy who experienced complications increased from 14% to 18%,” largely due to infection. They concluded that the relative risk of biopsy side effects for each patient “continues to increase.”

The records from which the authors drew their data offered insight into the patient risk factors most associated with biopsy complications. By correlating complications with demographics and clinical characteristics, they found that patients most in danger of morbidities, or side effects, were men older than 70 with a history of prostate cancer, or those with prior use of either fluoroquinolone antibiotics (e.g. for urinary tract infections) or anticoagulants (blood thinners).

Because little research has been done on biopsy complications, they also looked for factors that seem to put specific patients at higher risk. “They found that patients who were age 70 or older, those with a prior diagnosis of prostate cancer, or a history of fluoroquinolone antibiotics or anticoagulant use were at highest risk.”[ii] Knowing the factors that make some patients especially vulnerable to biopsy risks should help physicians establish priorities for each patient regarding the necessity for biopsy. Protective measures can be taken to make biopsies safer by strictly following prebiopsy and biopsy protocols. One member of the study team, Dr. R. J. Karnes, said, “Our findings indicate that we should focus further efforts on improving how we select patients to undergo a biopsy, how we prep them and, perhaps, even how we perform biopsies to reduce the complications associated with the procedure.” [iii]

It is worth noting that biopsy procedures such as the real-time MRI-guided targeted biopsy as performed at the Sperling Prostate Center minimizes biopsy risk in two important ways:

1. Using pre-biopsy 3T multiparametric MRI to rule a biopsy in or out by identifying any suspicious areas that may be present, and
2. Significantly reducing the number of biopsy needles by targeting those areas.

Not only do real-time MRI-guided targeted biopsies reduce the likelihood of complications, they also increase the diagnostic accuracy by sampling those regions most likely to harbor more dangerous cancer cells. The diagnostic pathway becomes more efficient and cost effective, thanks to identifying patients most in need of biopsy, and enhancing precise diagnosis while using a smaller number of needles.

As screening tests become more prostate cancer-specific, it is to be expected that the number of biopsies performed will diminish for a meaningful reason: if a blood or urine test can indicate the possibility that prostate cancer is present, and imaging can reveal the suspicious areas, only those men who truly require tissue sampling will undergo a prostate biopsy. And, with the aid of state-of-the-art MRI, the process itself will be more patient-friendly with more accurate findings.

[i] Gershman B, Van Houten HK, Herrin J, Moreira DM et al. Impact of Prostate-specific Antigen (PSA) Screening Trials and Revised PSA Screening Guidelines on Rates ofProstate Biopsy and Postbiopsy Complications. Eur Urol. 2016 Mar 16. pii: S0302-2838(16)00272-4. doi: 10.1016/j.eururo.2016.03.015. [Epub ahead of print]

[ii] Prostate-specific antigen screening publications influence biopsy rates, associated complications. Science Daily, March 31 2016. https://www.sciencedaily.com/releases/2016/03/160331134417.htm

[iii] Ibid.