Improved Detection of Higher Risk Prostate Cancer by MRI-Targeted Versus Standard Template Ultrasound-Guided Biopsy
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IMPORTANCE: The majority of new prostate cancer (PCa) diagnoses made in the United States occur via transrectal ultrasound (TRUS) guided systematic template prostate biopsy ("standard biopsy"). Since this modality depends on random sampling of the organ, which may lead to undersampling of aggressive disease in addition to detection of low-risk PCa with concomitant harms of overtreatment, there is a demand for more reliable and accurate diagnostic methods. Multiparametric magnetic resonance imaging (MP-MRI) of the prostate can identify lesions suspicious for PCa, and platforms using software fusion of pre-acquired MRI with real-time TRUS ("MRI-targeted biopsy") are now FDA-approved. OBJECTIVE: To assess whether MRI-targeted biopsy detects a significantly greater proportion of higher-grade, clinically-significant disease as compared to standard biopsy ("upgrading") in patients who underwent both approaches. DESIGN: Prospective cohort study of men undergoing both MRI-targeted and standard biopsy from the National Cancer Institute (NCI) and UT Southwestern from 2007 to 2017. Pathology was categorized by the International Society of Urological Pathology grading scheme and compared between targeted biopsy and concurrent standard biopsy with McNemar's test. Parameters associated with upgrading, determined by threshold p<0.15, were evaluated in multivariable logistic regression models where significance was defined as p<0.05. INTERVENTIONS: Following referral for elevated serum prostate-specific antigen (PSA), patients underwent MP-MRI. Men with lesions suspicious for PCa on MRI underwent a single biopsy session during which targeted biopsy and standard biopsy were performed concurrently. RESULTS: Of 1913 men in the study, 1235 were diagnosed with PCa by either standard or targeted biopsy. Patients between the two centers were matched by age and PSA (Table 1) but differed by history of previous biopsy, MRI prostate volume, and racial distribution. 408 patients had intermediate to high grade prostate cancer diagnosed by either targeted or standard biopsy (Table 2), of whom 194 (47%) had concordant targeted and standard biopsy results. 151 (37%) men had intermediate to high grade disease missed or downgraded relative to targeted biopsy by standard biopsy, and 63 men (15%) were missed or downgraded relative to standard biopsy by targeted biopsy (p<0.0001). On multivariable analysis of upgrading by targeted biopsy, when controlling for potentially confounding factors, increasing age, MRI prostate volume, number of targets and PSA remained significantly associated, whereas the performing center was not predictive. CONCLUSIONS: MRI-targeted prostate biopsy results in greater detection of clinically significant higher-grade PCa as compared to standard biopsy. Whether MRI-targeted biopsy can be performed instead of standard biopsy, versus being performed in selected risk-stratified populations or as a supplemental technique, requires additional study.