Faculty Bibliography

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: To assess associations between whole-lesion apparent diffusion coefficient (ADC) metrics and pathologic findings of Likert score 3 prostate lesions at MRI/ultrasound fusion targeted biopsy. METHODS: This retrospective Institutional Review Board-approved study received a waiver of consent. We identified patients receiving a highest lesion score of 3 on 3 Tesla multiparametric MRI reviewed by a single experienced radiologist using a 5-point Likert scale and who underwent fusion biopsy. A total of 188 score 3 lesions in 158 patients were included. Three-dimensional volumes-of-interest encompassing each lesion were traced on ADC maps. Logistic regression was used to predict biopsy results based on whole-lesion ADC metrics and patient biopsy history. Biopsy yield was compared between metrics. RESULTS: By lesion, targeted biopsy identified tumor in 22.3% and Gleason score (GS) > 6 tumor in 8.5%, although results varied by biopsy history: biopsy-naive (n = 80), 20.0%/8.8%; prior negative biopsy (n = 53), 9.4%/1.9%; prior positive biopsy (n = 55): 40.0%/14.5%. Biopsy history, whole-lesion mean ADC, whole-lesion ADC10-25 , and whole-lesion ADC25-50 were each significantly associated with tumor or GS > 6 tumor at fusion biopsy (P 6 tumor, which was significantly higher (P < 0.001) than specificity of PSA (17.5%) at identical sensitivity. CONCLUSION: For score 3 lesions in patients without prior negative biopsy, whole-lesion ADC metrics help detect GS > 6 cancer while avoiding negative biopsies. However, deferral of fusion biopsy may be considered for score 3 lesions in patients with prior negative biopsy (without applying whole-lesion ADC metrics) given exceedingly low ( approximately 2%) frequency of GS > 6 tumor in this group. J. Magn. Reson. Imaging 2015.

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.