among men with MRI-visible lesions in a single-center study.
Compared with either method alone, a combination of the two biopsy methods resulted in 9.9% more prostate cancer diagnoses, explained study author Michael Ahdoot, MD, of the National Institutes of Health and colleagues. Their report was published in the New England Journal of Medicine.
“With the addition of MRI-targeted biopsy to systematic biopsy, we may have entered an era of increased diagnostic certainty in prostate cancer,” the researchers wrote.
Their single-center, comparative diagnostic study included 2,103 patients with MRI-visible prostate lesions who underwent both systematic and MRI-targeted biopsy. In cases of multiple biopsies, only the results of the initial biopsies were included.
Each individual specimen was assigned a Gleason score by a genitourinary pathologist and was subsequently categorized into a grade group on a scale of 1-5, with higher scores reflecting greater cancer risk. Grade group 1 was defined as clinically insignificant disease. Grade group 2 was defined as favorable intermediate-risk disease. Grade group 3 or higher was defined as unfavorable intermediate-risk disease or worse.
The primary endpoints were cancer detection rates for each biopsy method, based on grade group. “Among the men who underwent subsequent radical prostatectomy, upgrading and downgrading of grade group from biopsy to whole-mount histopathological analysis of surgical specimens [was also assessed],” the researchers explained.
Among patients who underwent combined biopsy, prostate cancer was identified in 62.4% of patients, and 19.2% underwent radical prostatectomy.
For grade groups 3-5, rates of cancer detection were significantly higher with MRI-targeted biopsy than with systematic biopsy (P less than .01 for all). For grade group 1, detection rates were significantly lower with MRI-targeted biopsy (P less than .01).
“Although many of [the] benefits resulted from MRI-targeted biopsy alone, omission of systematic biopsy would have led to missing the diagnosis of 8.8% of clinically significant cancers,” the researchers reported.
In addition, among patients who underwent radical prostatectomy, the rates of upgrading (grade group 3 or higher) on histopathological analysis were lower for combined biopsy (3.5%) than for MRI-targeted biopsy (8.7%) and systematic biopsy (16.8%).
The researchers acknowledged that a key limitation of this study was the single-center design. As a result, the findings may not be generalizable to other institutions.
However, the researchers concluded that “these findings suggest that combined biopsy provides improved diagnostic accuracy over either systematic or MRI-targeted biopsy alone and better predicts the results of final histopathological analysis.”
The study was funded by the National Institutes of Health, Philips, and the Dr. Mildred Scheel Foundation for Cancer Research. The authors disclosed financial affiliations with Philips, Biocompatibles UK, Boston Scientific, Celsion, and other companies.
SOURCE: Ahdoot M et al. N Engl J Med. 2020 Mar 4. doi: 10.1056/NEJMoa1910038.
