Faculty Bibliography

OBJECTIVES: To evaluate the cancer detection rates (CDR) for men undergoing 12 core systematic prostate biopsy with negative prebiopsy mpMRI (NegMR). MATERIALS & METHODS: Clinical data from consecutive men undergoing prostate biopsy with prebiopsy 3T mpMRI from December 2011 to August 2014 were reviewed from an IRB approved prospective database. Prebiopsy mpMRI was read by a single radiologist and men with NegMR prior to biopsy were identified for this analysis. Clinical features, CDR, and NPV rates were summarized. RESULTS: Seventy five men underwent SPB with a NegMRI during the study period. For the entire cohort, men with no prior biopsy, men with prior negative biopsy, and men enrolled in active surveillance protocols, overall CDR was 18.7%, 13.8%, 8.0% and 38.1%, respectively, and detection of Gleason sum >/= 7 (GS>/=7) cancer was 1.3%, 0%, 4.0% and 0%, respectively. The NPV for all cancers was 81.3%, 86.2%, 92.0%, and 61.9%, and for GS>/=7 cancer was 98.7%, 100%, 96.0% and 100%, respectively. CONCLUSIONS: Negative prebiopsy mpMRI confers an overall NPV of 82% on 12 core biopsy for all cancer and 98% for GS>/=7. Based upon biopsy indication, these findings assist in prebiopsy risk stratification for detection of high risk disease and may provide guidance in the decision to pursue biopsy

INTRODUCTION: There is increasing interest in using imaging in the detection and localization of prostate cancer (PCa). Both multiparametric magnetic resonance imaging (mpMRI) and HistoScanning (HS) have been independently evaluated in the detection and localization of PCa. We undertook a prospective, blinded comparison of mpMRI and HS for cancer localization among men undergoing radical prostatectomy. METHODS: Following approval by the institutional review board, men scheduled to undergo radical prostatectomy, who had previously undergone mpMRI at our institution, were offered inclusion in the study. Those consenting underwent preoperative HS following induction of anesthesia; mpMRI, HS, and surgical step-section pathology were independently read by a single radiologist, urologist, and pathologist, respectively, in a blinded fashion. Disease maps created by each independent reader were compared and evaluated for concordance by a 5 persons committee consisting of 2 urologists, 2 pathologists, and 1 radiologist. Logistic regression for correlated data was used to assess and compare mpMRI and HS in terms of diagnostic accuracy for cancer detection. Generalized estimating equations based on binary logistic regression were used to model concordance between reader opinion and the reference standard assessment of the same lesion site or region as a function of imaging modality. RESULTS: Data from 31/35 men enrolled in the trial were deemed to be evaluable. On evaluation of cancer localization, HS identified cancer in 36/78 (46.2%) regions of interest, as compared with 41/78 (52.6%) on mpMRI (P = 0.3968). The overall accuracy, positive predictive value, negative predictive value, and specificity for detection of disease within a region of interest were significantly better with mpMRI as compared with HS. HS detected 36/84 (42.9%) cancer foci as compared with 42/84 (50%) detected by mpMRI (P = 0.3678). Among tumors with Gleason score>6, mpMRI detected 19/22 (86.4%) whereas HS detected only 11/22 (50%, P = 0.0078). Similarly, among tumors>10mm in maximal diameter, mpMRI detected 28/34 (82.4%) whereas HS detected only 19/34 (55.9%, P = 0.0352). CONCLUSION: In our institution, the diagnostic accuracy of HS was inferior to that of mpMRI in PCa for PCa detection and localization. Although our study warrants validation from larger cohorts, it would suggest that the HS protocol requires further refinement before clinical implementation.

BACKGROUND: Increasing evidence supports the use of magnetic resonance imaging (MRI)-ultrasound fusion-targeted prostate biopsy (MRF-TB) to improve the detection of clinically significant prostate cancer (PCa) while limiting detection of indolent disease compared to systematic 12-core biopsy (SB). OBJECTIVE: To compare MRF-TB and SB results and investigate the relationship between biopsy outcomes and prebiopsy MRI. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of a prospectively acquired cohort of men presenting for prostate biopsy over a 26-mo period. A total of 601 of 803 consecutively eligible men were included. INTERVENTIONS: All men were offered prebiopsy MRI and assigned a maximum MRI suspicion score (mSS). Men with an MRI abnormality underwent combined MRF-TB and SB. OUTCOMES: Detection rates for all PCa and high-grade PCa (Gleason score [GS] >/=7) were compared using the McNemar test. RESULTS AND LIMITATIONS: MRF-TB detected fewer GS 6 PCas (75 vs 121; p<0.001) and more GS >/=7 PCas (158 vs 117; p<0.001) than SB. Higher mSS was associated with higher detection of GS >/=7 PCa (p<0.001) but was not correlated with detection of GS 6 PCa. Prediction of GS >/=7 disease by mSS varied according to biopsy history. Compared to SB, MRF-TB identified more GS >/=7 PCas in men with no prior biopsy (88 vs 72; p=0.012), in men with a prior negative biopsy (28 vs 16; p=0.010), and in men with a prior cancer diagnosis (42 vs 29; p=0.043). MRF-TB detected fewer GS 6 PCas in men with no prior biopsy (32 vs 60; p<0.001) and men with prior cancer (30 vs 46; p=0.034). Limitations include the retrospective design and the potential for selection bias given a referral population. CONCLUSIONS: MRF-TB detects more high-grade PCas than SB while limiting detection of GS 6 PCa in men presenting for prostate biopsy. These findings suggest that prebiopsy multiparametric MRI and MRF-TB should be considered for all men undergoing prostate biopsy. In addition, mSS in conjunction with biopsy indications may ultimately help in identifying men at low risk of high-grade cancer for whom prostate biopsy may not be warranted. PATIENT SUMMARY: We examined how magnetic resonance imaging (MRI)-targeted prostate biopsy compares to traditional systematic biopsy in detecting prostate cancer among men with suspicion of prostate cancer. We found that MRI-targeted biopsy detected more high-grade cancers than systematic biopsy, and that MRI performed before biopsy can predict the risk of high-grade cancer.

OBJECTIVE: To report outcomes of MRI-ultrasound fusion (MRF-TB) and 12-core systematic biopsy (SB) over a 26-month period in men with prior negative prostate biopsy. METHODS: Between 6/12 and 8/14, 210 men presenting to our institution for prostate biopsy with >/=1 prior negative biopsy underwent multiparametric MRI followed by MRF-TB and SB and were entered into a prospective database. Clinical characteristics, MRI suspicion scores (mSS), and biopsy results were queried from the database and the detection rates of Gleason >/=7 prostate cancer (PCa) and overall PCa were compared between biopsy techniques using McNemar's test. RESULTS: Fifty-three (31%) of 172 men meeting inclusion criteria (mean age 65+/-8 years; mean PSA 8.9+/-8.9) were found to have PCa. MRF-TB and SB had overall cancer detection rates (CDR) of 23.8% and 18.0% (p=0.12), respectively, and CDR for Gleason score (GS)>/=7 disease of 16.3% and 9.3% (p=0.01), respectively. Of 31 men with GS>/=7 disease, MRF-TB detected 28 (90.3%) while SB detected 16 (51.6%) (p<0.001). Using UCSF-CAPRA criteria, only one man was re-stratified from low-risk to higher risk based on SB results compared to MRF-TB alone. Among men with mSS<4, 80% of detected cancers were low-risk by UCSF-CAPRA criteria. CONCLUSIONS: In men with previous negative biopsies and persistent suspicion for PCa, SB contributes little to the detection of GS>/=7 disease by MRF-TB, and avoidance of SB bears consideration. Based on the low likelihood of detecting GS>/=7 cancer and overall low-risk features of PCa in men with mSS<4, limiting biopsy to men with mSS>/=4 warrants further investigation.