MRI-targeted biopsies alone may underestimate grade of prostate cancer 

1. In this prospective cohort, MRI-targeted biopsies alone, underestimated the histologic grade of prostate cancer tumors.

2. The combination of MRI targeted biopsy and systematic biopsy led to greater detection of all prostate cancers, and the upgrade of tumors to grade 3 or higher on histopathological analysis, upon radical prostatectomy, were lower in the group.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Systematic biopsies for the initial diagnosis and grading of prostate cancer have resulted in undertreatment of patients with high-grade disease. Prostate multiparametric MRI allows for MRI-targeted biopsies which has been shown to improve detection of high-grade cancers than systematic biopsy. Prostate multiparametric MRI allowed for MRI-targeted biopsies which resulted in a larger rate of detection of high-grade cancers than systematic biopsy. The Trio Study, a sub-study within the Tracking Devices of Locate Abnormalities During Invasive Procedures clinical trial, assessed the MRI-targeted, systematic, and combined biopsy to define the most effective method for prostate cancer diagnosis. The primary outcome of cancer detection for each biopsy method, as assessed by grade group, indicated a more accurate prediction of a patient’s true pathological grade group with the combined biopsy detection. Using histopathology, after radical prostatectomy, the combined biopsy detection showed fewer upgrade reclassification to grade 3 or higher. The prospective cohort study provided evidence the combined biopsy detection method more accurately predicted the patient’s true pathological grade group when compared to the gold standard of whole-mount histopathological analysis. Limitations included reproducibility of results with less experienced practitioners, referral basis of patients participating in the study not mirroring the disease in the general population, and potential MRI scan labelling errors resulting in bias.

Click to read the study in NEJM

Relevant Reading: Comparison of Targeted vs Systematic Prostate Biopsy in Men Who Are Biopsy Naive: The Prospective Assessment of Image Registration in the Diagnosis of Prostate Cancer (PAIREDCAP) Study

In-Depth [prospective cohort]: The prospective cohort study enrolled 2103 men at the National Cancer Institute (NCI) from 2007 to 2019. Inclusion criteria included adult men (≥ 18 years of age), elevated serum prostate-specific antigen (PSA) level, abnormal digital rectal exam, and the presence of a prostate lesion on MRI. Exclusion criteria included previous treatment for prostate cancer, the absence of visible prostate lesions on MRI, or the inability to undergo an MRI. All patients underwent the MRI-targeted and systematic biopsies. One physician conducted the MRI-targeted biopsy by superimposing the T₂-weighted MRI images onto real-time prostate ultrasonographic scans. Another physician performed the 12-core systematic biopsy with ultrasonographic guidance. The biopsies were classified into grade groups ranging from 1 to 5 for systematic, MRI-targeted, and combined (systematic and MRI-targeted) biopsies. Clinically significant disease was classified as grade group 3 or higher. When compared to systematic biopsies, MRI-targeted biopsy detection led to more diagnoses in grade 3 (p=0.004), 4 (p<0.001), and 5 (p=0.003). No detection of cancer for grade group 3 or higher would have occurred for 41 patients with MRI-targeted detection alone, without additional systematic biopsy. Of the 466 patient lesions classified as grade group 3 or higher, 175 were detected by MRI-targeted biopsy only and 41 were detected by systematic biopsy alone. Among the group of patients undergoing a radical prostatectomy after their biopsies, upgrading occurred on histopathological analysis to clinically significant disease (grade group ≥3) for systematic (41.6%), MRI-targeted (30.9%), and combined (14.4%) biopsies.

Image: PD

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