New Biopsy Method Ups Detection of High-Risk Prostate Cancer

A targeted magnetic resonance (MR)/ultrasound fusion–guided biopsy technique produced better results than a standard biopsy in the detection of high-risk prostate cancer. This new technique also diagnosed fewer cases of low-risk prostate cancer. The results of this prospective study were published in JAMA.

The standard core needle biopsy technique is invasive, involving the removal of prostate tissue with a thin needle, which is then analyzed by a pathologist to detect abnormal, malignant cells.

The newer biopsy approach was better able to differentiate between low-risk and intermediate- and high-risk prostate tumors compared with either the standard core needle biopsy or the two techniques used together.

“This study demonstrated that targeted biopsy could significantly change the distribution of risk in men newly diagnosed with prostate cancer toward diagnosis of more high­risk disease,” said the study authors in their discussion. Still, this study is preliminary, and further studies that can link diagnosis with disease recurrence and prostate cancer mortality are needed.

The patients in the study underwent a relatively new imaging modality, multiparametric magnetic resonance imaging (MP-MRI), followed by targeted MR/ultrasound fusion biopsy and concurrent standard biopsy.

The current study is among the first to show that the targeted MR/ultrasound biopsy alone is sufficient to detect intermediate- to high-risk prostate cancer.

M. Minhaj Siddiqui, MD, of the University of Maryland in Baltimore, Peter A. Pinto, MD, of the urologic oncology branch at the National Cancer Institute in Bethesda, Maryland, and colleagues, compared outcomes among 1,003 men who underwent both a standard biopsy and a concurrent targeted biopsy between 2007 and 2014 at the National Cancer Institute.

Sixty-nine percent of prostate cancer diagnoses were in agreement between the two techniques. Overall, the targeted biopsy approach diagnosed 461 cases of prostate cancer compared with 469 cases that were diagnosed with a standard biopsy. But, the targeted biopsy diagnosed 30% more high-risk prostate cancers compared with standard biopsies-173 cases vs 122 cases, respectively. The new approach also detected 17% fewer low-risk cancers-213 cases vs 258 cases, respectively.

Combining the two biopsy techniques was not useful, according to the authors, since 200 men needed to be biopsied by the combination to diagnose one additional high-risk tumor. The combination of both biopsy approaches resulted in 22% more cancer cases (103 cases), but 83% of these were low-risk cancers. Only 5% were high-risk cancers.

The authors noted that, in the current study, the imaging biopsies were analyzed by two genitourinary radiologists with experience in interpreting these targeted biopsy results. “Reproducing these findings may be challenging until sufficient experience in the interpretation of these studies has been attained at centers newly adapting this technology,” stated the authors.

In an accompanying editorial, Lawrence H. Schwartz, MD, of the Columbia University College of Physicians and Surgeons in New York, and Ethan Basch, MD, of the Lineberger Comprehensive Cancer Center at the University of North Carolina, Chapel Hill, wrote that, “It remains unknown if use of this technique and shifts in cancer grade among patients who underwent biopsy will translate into clinically meaningful outcomes such as benefits in symptoms, functional status, or survival.”

“Any test that can inform decision making and potentially spare patients harm is immediately appealing, even if the effect on clinical outcomes is unknown,” said the editorial authors. But, they also stated that such a test should not be widely adopted “in the absence of direct evidence showing benefits on quality of life, life expectancy, or ideally both.”