Multi-institutional Assessment of Performance Metrics for MRI-targeted Transperineal Prostate Biopsy
William Martin, BS1, Johnathan Drevik, MD, MS2, Christian Schaufler, MD3, Ryan Daigle, BS1, Serge Ginzburg, MD2, Alexander Kutikov, MD, FACS4, Carl Gjertson, MD1, Peter Albertsen, MD1, Benjamin T. Ristau, MD, MHA1.
1UConn Health, Farmington, CT, USA, 2Einstein Healthcare Network, Philadelphia, PA, USA, 3Beth Israel Lahey Health, Boston, MA, USA, 4Temple Health, Philadelphia, PA, USA.
BACKGROUND: MRI-targeted biopsy (TB) combined with systematic biopsy has emerged as the optimal strategy for prostate cancer detection in the United States. Actionable Intelligence Metric (AIM) and Reduction Metric (ReM) have previously been defined in a transrectal prostate biopsy cohort to assess deliverables of TB. AIM measures the value add of TB over systematic biopsy alone for prostate cancer detection. ReM measures the ability of TB to detect prostate cancer in the absence of a systematic template. These metrics have not yet been applied in the transperineal prostate biopsy (TP-B) setting. We assessed the performance of AIM and ReM in men undergoing TP-B.
METHODS: Patients with prostate lesions on MRI who underwent concurrent TB and systematic TP-B tracked in prospectively maintained databases in two academic centers were included. Cognitive fusion was used to obtain 1-4 TBs of each identified lesion. Actionable intelligence metric (AIM) = [higher Grade Group (GG) on TB (minimum GG≥2) relative to TP-B] ¸ [total pts with GG≥2] (i.e. % for whom TB offered actionable data over systematic TP-B). Reduction metric (ReM) = 1 - [all pts with higher GG on TP-B (minimum GG≥2) relative to TB ¸ total pts undergoing biopsy] (i.e. % of men in whom systematic TP-B could have been avoided). AIM and ReM were compared among groups based on indication for biopsy and PI-RADS lesion on MRI. Differences between proportions were determined using a chi-squared test. A p < 0.05 was considered statistically significant.
RESULTS: 120 men (median age 66y, IQR 60.3-70y; median PSA 9.2ng/ml, IQR 5.7-13.6 ng/ml; median prostate volume 43 cm3, IQR 31.3-62.5 cm3) were included: 46 biopsy na´ve (BN), 31 men with prior negative biopsy (PNB), and 43 men on an active surveillance (AS). From this cohort, 13 men had MRI demonstrating highest PI-RADS lesion severity of 3, 60 had highest PI-RADS of 4, and 47 had highest PI-RADS of 5. Overall AIM and ReM for the cohort was 21.4% and 78.3%; 15.4% and 80.4% for BN, 15.8% and 67.7% for PNB, and 32.0% and 83.7% for AS. There was no significant difference between the AIM or ReM values based on indication for biopsy (p=0.275, p=0.234). AIM and ReM were 25.0% and 76.9% for patients with PI-RADS 3 lesions; 25.9% and 81.7% for patients with PI-RADS 4 lesions; 17.1% and 74.5% for PI-RADS 5. There was no difference in AIM (p=0.682) or ReM (p=0.663) based on PI-RADS score.
CONCLUSIONS: AIM and ReM remain useful tools to evaluate and compare deliverables of TB in the TP-B setting. TB adds value over systematic biopsy alone in 15-21% of patients. ReM values suggest that omitting systematic biopsy misses clinically significant cancers in up to 25% of patients. Combined TB and systematic biopsy remain the optimal approach for finding clinically significant prostate cancers in the TP-B setting. Findings are limited by moderate sample size. Further validation in a larger cohort is planned.
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