Targeted biopsy 'better at detecting high-risk prostate cancers than standard biopsy'

If results of a prostate-specific antigen test or digital rectal exam are positive, the next port of call is normally a prostate biopsy to confirm whether cancer is present. 

In a new study published in JAMA, researchers claim a targeted biopsy method is much more accurate in detecting high-risk prostate cancers than the standard biopsy technique.

Targeted biopsy using a combination of MRI and ultrasound identified 30% more high-risk prostate cancers than standard biopsy, a study found.

The standard method of prostate biopsy, also referred to as a core needle biopsy, involves a doctor removing samples of tissue from the prostate using a thin, hollow needle. 

The samples are then sent to a pathologist who views them under a microscope and assesses them for cell abnormalities that indicate cancer.

But the research team, at the University of Maryland School of Medicine, says the technique used in their study involves a combination of ultrasound and magnetic resonance imaging (MRI), which they say can effectively differentiate high-risk prostate cancers from those that are low risk.

The researchers said that, there is a concern that we overdiagnose and overtreat low-risk cancers that are unlikely to be terminal, and this technology enables us to make a more reliable diagnosis than the current standard practice.

According to the background information of the study, the accuracy of prostate cancer detection with targeted biopsy alone compared with that of standard biopsy has been unclear, as has the accuracy of both methods combined.

The research team analyzed 1,003 men who had been referred for biopsy following either a positive prostate-specific antigen (PSA) test or a digital rectal examination (DRE). All men received a standard biopsy and a targeted ultrasound/MRI biopsy, and the researchers compared the prostate cancer detection accuracy of each method.

The results of the analysis revealed that 461 prostate cancer cases were diagnosed with standard biopsy and 469 were diagnosed with targeted biopsy. In 69% of cases, both methods revealed the same outcomes.

However, the research team found that the targeted biopsy identified 30% more high-risk cancers than the standard biopsy and 17% fewer low-risk cancers. A combination of both targeted and standard biopsy led to 22% more low-risk cancers being diagnosed.

In addition, the research team used each technique to assess biopsied tissue and tissue taken from the prostate of 170 men who underwent a prostatectomy - surgical removal of the prostate gland.

From this, they found that the targeted biopsy was better at identifying low- and intermediate-risk prostate cancers than the standard biopsy.

Targeted therapy may 'enhance ability to identify patients with high-risk prostate cancers'

Because current diagnostic techniques for prostate cancer are unable to determine between aggressive and nonaggressive types, most patients who test positive for the disease receive treatment for it, such as radiation therapy or a prostatectomy.

However, the majority of men diagnosed with prostate cancer have tumors that progress so slowly that they may never experience cancer-related complications, meaning they may receive unwarranted cancer treatment.

As such, these latest findings are important as they suggest potential for a more accurate diagnostic method for prostate cancer.

"This study demonstrates that targeted fusion-guided biopsy could significantly enhance our ability to identify patients with high-risk prostate cancers that need more aggressive treatment.

While these findings could translate into substantial benefit to patients, this study is preliminary with regard to clinical endpoints, such as recurrence of disease and prostate cancer-specific mortality."

The research team says further studies are warranted to assess how targeted biopsy affects the clinical outcomes of patients with prostate cancer.

In an editorial linked to the study, another team of clinicians at Columbia University College of Physicians and Surgeons in New York, NY, at the University of North Carolina and associate editor of JAMA, say any test that has the potential to improve diagnosis and reduce any unnecessary treatment is "appealing."

"Nonetheless," they add, "a new test should not be widely adopted in the absence of direct evidence showing benefits on quality of life, life expectancy, or ideally both. 

Therefore, the scientific community has the responsibility to ensure through clinical research that promising new technologies such as MR/ultrasound fusion imaging-guided biopsies bring value to patients."

References:

1.     Comparison of MR/ultrasound fusion-guided biopsy with ultrasound-guided biopsy for the diagnosis of prostate cancer, Mohammad Minhaj Siddiqui, et al., JAMA, doi:10.1001/jama.2014.17942, published online 27 January 2015, abstract.

2.     MR/ultrasound fusion-guided biopsy in prostate cancer: what Is the evidentiary standard?, Lawrence H. Scwartz, Ethan Basch,JAMA, doi:10.1001/jama.2014.17943, published online 27 January 2015, editorial.

3.     JAMA news release, accessed 26 January 2015.

4.     University of Maryland news release, accessed 26 January 2015 via Newswise.