Magnetic Resonance Imaging-guided In-bore and Magnetic Resonance Imaging-transrectal Ultrasound Fusion Targeted Prostate Biopsies: An Adjusted Comparison of Clinically Significant Prostate Cancer Detection Rate.

BACKGROUND: With the increasing adoption of targeted prostate biopsies, it becomes important to understand the strengths and shortcomings of the techniques available for targeting suspicious lesions. OBJECTIVE: To compare clinically significant prostate cancer (csPCa) detection rate with magnetic resonance imaging-transrectal ultrasound (MRI-TRUS) fusion versus in-bore biopsy in men with abnormal multiparametric MRI (mpMRI). DESIGN, SETTING, AND PARTICIPANTS: This single-center, retrospective analysis of prospectively generated data included all men with abnormal mpMRI and fusion or in-bore biopsy between May 2017 and April 2018. Grade group (GG) 2-5 cancers were considered csPCa. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Detection of csPCa was adjusted according to patient- and lesion-related characteristics using propensity score weighting. Secondary endpoints included the detection of clinically insignificant tumors and the rate of GG upgrade from biopsy to prostatectomy specimen. Analyses were performed at patient and lesion levels. RESULTS AND LIMITATIONS: A total of 103 and 300 men were included in the in-bore and fusion cohorts, respectively. On a per-patient basis, in-bore biopsies detected a higher proportion of csPCa (61%, 63/103) than fusion plus systematic biopsies (47%, 141/300; adjusted odds ratio [OR]: 2.1, 95% confidence interval [CI]: 1.6-2.8, p<0.0001). In-bore biopsies also detected fewer (11%, 11/103) clinically insignificant cancers than fusion biopsies (18%, 53/300; OR: 0.5, 95% CI: 0.3-0.8, p=0.001). Of those who had radical prostatectomy, GG upgrade after surgery was seen in 17% (4/24) of the men in the in-bore cohort and in 27% (22/82) of the men in the fusion cohort (p=0.55). CONCLUSIONS: MRI-guided in-bore biopsies detected more clinically significant and fewer insignificant prostate cancers than MRI-TRUS fusion targeted biopsies. Further cost-utility and patient outcome analyses are needed. PATIENT SUMMARY: In-bore biopsies (where the patient is on the magnetic resonance imaging [MRI] scanner itself) detected more aggressive cancers and fewer indolent cancers than fusion (where software blends MRI and ultrasound images) biopsies. These findings may help patients and physicians choose the best biopsy approach.

Prospective Inclusion of Apparent Diffusion Coefficients in Multiparametric Prostate MRI Structured Reports: Discrimination of Clinically Insignificant and Significant Cancers.

OBJECTIVE: The purpose of this study was to assess the diagnostic performance of prospectively assigned mean apparent diffusion coefficient (ADC) values in multiparametric MRI (mpMRI) structured reports for discriminating clinically insignificant (International Society of Urological Pathology [ISUP] group 1) from clinically significant (ISUP groups 2-5) prostate cancer. MATERIALS AND METHODS: This single-center study included men with abnormal 3-T mpMRI findings (Prostate Imaging Reporting and Data System version 2 score, ≥ 3) who subsequently underwent radical prostatectomy or targeted biopsy with positive results. One of nine radiologists prospectively reported the mean ADC for each lesion during clinical interpretation. Lesions with ADC ≤ 0.700 mm2/s × 10-3 were flagged as concerning for clinically significant prostate cancer. The index lesion at MRI correlated with the site-concordant lesion at targeted biopsy or whole-mount histopathologic analysis. Logistic regression was used to evaluate the utility of mean ADC values for discriminating ISUP grade group 1 from groups 2-5. Diagnostic performance was assessed by ROC AUC. RESULTS: Among the 218 eligible men, those with ISUP group 2-5 lesions had lower mean ADC values than those with ISUP 1 lesions; overall, 0.598 vs 0.803 mm/s2 × 10-3 (p < 0.0001); peripheral zone (PZ), 0.597 vs 0.855 mm/s2 × 10-3 (p < 0.0001); transition zone (TZ), 0.600 vs 0.660 mm/s2 × 10-3 (p = 0.035). The AUC for the PZ was 0.91 and for the TZ was 0.70. The optimal ADC cutoff values were 0.682 mm/s2 × 10-3 for PZ lesions and 0.638 mm2/s × 10-3 for TZ lesions, resulting in sensitivity and specificity of 78% and 94% for the PZ and 72% and 67% for the TZ. CONCLUSION: ADC values estimated prospectively in a clinical setting can help differentiate clinically insignificant from clinically significant prostate cancer, facilitating prebiopsy and pretreatment risk stratification.