In a study reported in The New England Journal of Medicine, Ahdoot et al found that combined use of magnetic resonance imaging (MRI)-targeted biopsy and 12-core systematic prostate biopsy led to enhanced detection of prostate cancers vs either approach alone in men with MRI-visible prostate lesions.
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Study Details
The study involved 2,103 men at the National Cancer Institute who underwent biopsy by both methods. The primary outcome was cancer detection according to grade group: grade group 1 (Gleason score of 3+3 = 6) was defined as clinically insignificant disease; grade group 2 or higher (Gleason score of 3+4 = 7) was defined as cancer with favorable intermediate risk or worse; and grade group 3 or higher (Gleason score of 4+3 = 7) was defined as cancer with unfavorable intermediate risk or worse.
Key Findings
Among the 2,103 men, cancer was diagnosed in 1,312 (62.4%) by a combination of the two methods; 404 (19.2%) underwent radical prostatectomy. Cancer was diagnosed by systematic biopsy alone in 1,104 patients (52.5%) and by MRI-targeted biopsy alone in 1,084 (51.5%).
With MRI-targeted biopsy, cancer detection rates were significantly lower vs systematic biopsy for grade group 1 cancers and significantly higher for grade groups 3 through 5 cancers (P < .01 for all comparisons).
Combined biopsy led to cancer diagnosis in 208 more men (9.9%) than with either method alone, and to upgrading to a higher grade group in 458 men (21.8%). If only MRI-targeted biopsies had been performed, 8.8% of clinically significant cancers would have been misclassified.
Among the 404 men who underwent radical prostatectomy, combined biopsy was associated with a lower rate of upgrade to grade group 3 or higher on histopathologic analysis of surgical specimens (3.5%) compared with MRI-targeted biopsy (8.7%) and systematic biopsy (16.8%).
The investigators concluded, “Among patients with MRI-visible lesions, combined biopsy led to more detection of all prostate cancers. However, MRI-targeted biopsy alone underestimated the histologic grade of some tumors. After radical prostatectomy, upgrades to grade group 3 or higher on histopathological analysis were substantially lower after combined biopsy.”
Disclosure: The study was funded by the National Institutes of Health and others. For full disclosures of the study authors, visit nejm.org.
