Combined biopsy approach improves prostate cancer detection
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A combined screening approach of systematic and MRI-targeted biopsy improved detection of all prostate cancers among men with MRI-visible lesions, according to results of a prospective study published in The New England Journal of Medicine.
MRI-targeted biopsy alone underestimated the histologic grade of some tumors, researchers noted. Following radical prostatectomy, upgrades to the highest grade group on histopathological analysis occurred much less frequently after combined biopsy.
“I was always bothered by the fact that we had a screening process of a blood biomarker, called PSA, that was not specific to prostate cancer,” Peter A. Pinto, MD, investigator and faculty member in the urologic oncology branch of the NCI, told Healio. “Elevated PSAs can come from noncancerous reasons, and the biopsy is blind to the tumor location.
“The NIH and NCI research team has published many papers on this topic suggesting that men undergo a prostate MRI after the PSA is elevated but before the biopsy,” he added. “Men with elevation of PSA undergo biopsy for no reason if the PSA was elevated for noncancerous reasons. We can add a filter to avoid a biopsy if there is nothing concerning. If there is something concerning, we can do a biopsy of that specific area.”
Pinto and colleagues analyzed 2,103 men (mean age, 63.3 years; 78.6% white) with MRI-visible prostate lesions who underwent both MRI-targeted and 12-core systematic prostate biopsy.
Cancer detection according to grade group — a clustering of Gleason grades — served as the study’s primary endpoint. Grade group 1 referred to clinically insignificant disease, grade group 2 or higher referred to cancer with favorable intermediate risk or worse, and grade group 3 or higher referred to cancer with unfavorable intermediate risk or worse.
Researchers recorded the upgrading and downgrading of grade group from biopsy to whole-mount histopathological analysis of surgical specimens among men who underwent subsequent radical prostatectomy.
The detection of grade group 2 or higher and grade group 3 and higher cancers, as well as cancer detection stratified by previous biopsy status and grade reclassification between biopsy and prostatectomy, served as secondary endpoints.
Of the 2,103 men who underwent both biopsy methods, 1,313 (62.4%) were diagnosed with cancer and 404 (19.2%) underwent subsequent radical prostatectomy. Median time from prostate biopsy to radical prostatectomy was 98 days (interquartile range, 74-134).
Results showed cancer detection rates appeared significantly lower on MRI-targeted biopsies vs. systematic biopsy for grade group 1 cancers, and they were significantly higher for grade group 3 and higher (P < .001).
Combined biopsies led to cancer diagnoses for 208 more men (9.9%) than with either biopsy alone. Adding MRI-targeted biopsy to systematic biopsy also led to upgrades to a higher grade group for 458 men (21.8%).
Had only MRI-targeted biopsies been performed, 8.8% of grade group 3 or higher cancers would have been misclassified.
Among men who underwent radical prostatectomy, combined biopsies appeared associated with fewer upgrades to clinically significant disease (3.5%) on histopathological analysis than MRI-targeted biopsy (8.7%) and systematic biopsy (16.8%).
Many practitioners involved in this study had experience performing and interpreting prostate MRI and prostate histopathological analysis; therefore, the results may not be reproducible at institutions with less-experienced clinicians, researchers wrote.
“When physicians are doing systematic biopsy, there is a 30% to 40% chance of missing cancer inside the prostate or underestimating how bad the cancer is,” Michael Ahdoot, MD, urologic oncology fellow in the urologic oncology branch at NCI, told Healio. “What this combined method is demonstrating is that this brings those rates down substantially. We are hoping that this makes physicians more confident in choosing the most appropriate treatments for their patients.” – by John DeRosier
For more information:
Peter A. Pinto, MD, can be reached at National Cancer Institute, Building 10, Hatfield CRC, Room 2W-5940, Bethesda, MD 20892-1107; email: pintop@mail.nih.gov.
Michael Ahdoot, MD, can be reached at National Cancer Institute, Building 10, Room 1-5940, Bethesda, MD 20892-1107; email: ahdootm@mail.nih.gov.
Disclosures: Ahdoot reports no relevant financial disclosures. Pinto reports a patent on a method and system for performing biopsies. Please see the study for all other authors’ relevant financial disclosures.
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