Background: Multiparametric prostate MRI (mpMRI) is being increasingly adopted for work-up of prostate cancer. For patients selected to omit biopsy, we identified factors associated with repeat MRI, eventual prostate biopsy, and subsequent detection of clinically significant prostate cancer (csPCa, Grade Group >= 2). Methods: We identified biopsy-na & iuml;ve men presenting with PSA 2-20 ng/mL (March 2018-June 2021) undergoing initial mpMRI with PIRADS 1-3 lesions who were not selected for biopsy with >= 6 months follow-up. We examined factors associated with repeat mpMRI, progression to biopsy, and subsequent detection of csPCa with univariable and multivariable logistic regression. Results: Of 1494 men, 31% (463/1494) did not pursue biopsy. PSA density (PSAD) <= 0.1, prostate health index (PHI) < 55, and PIRADS 1-2 were associated with omission of prostate biopsy. csPCa diagnosis-free survival was 97.6% (326/334) with median follow up of 23.1 months (IQR 15.1-34.6 months). Black race, PSA, PHI, PSA density, and PSA and PHI velocity were significant predictors of undergoing repeat mpMRI (15.6%, 52/334) and subsequent biopsy (8.4%, 28/334). 8 men were subsequently diagnosed with csPCa (N = 7 on prostate biopsy; N = 1 incidentally on holmium enucleation of prostate). All patients diagnosed with csPCa had PIRADS 4-5 on repeat mpMRI. Conclusions: The subsequent detection rate of csPCa among patients not initially biopsied after mpMRI was low at 2.4%. Decisions to omit biopsy after initial reassuring PHI, PSAD, and mpMRI appear safe with subsequent reassuring serum biomarkers and for cause mpMRI during follow-up.

The National Comprehensive Cancer Network (NCCN) very low risk (VLR) category for prostate cancer (PCa) represents clinically insignificant disease, and detection of VLR PCa contributes to overdiagnosis. Greater use of magnetic resonance imaging (MRI) and biomarkers before patient selection for prostate biopsy (PBx) reduces unnecessary biopsies and may reduce the diagnosis of clinically insignificant PCa. We tested a hypothesis that the proportion of VLR diagnoses has decreased with greater use of MRI-informed PBx using data from our 11-hospital system. From 2018 to 2023, 351/3197 (11%) men diagnosed with PCa met the NCCN VLR criteria. The proportion of VLR diagnoses did not change from 2018 to 2023 (p = 0.8) despite an increase in the use of MRI-informed PBx (from 49% to 82%; p < 0.001). Of patients who underwent combined systematic and targeted PBx and were diagnosed with VLR disease, cancer was found in systematic PBx regions in 79% of cases and in targeted PBx regions in 31% of cases. When performing both systematic and targeted PBx, prebiopsy MRI-based risk calculators could limit VLR diagnosis by 41% using a risk threshold of >5% for Gleason grade group ≥3 PCa to recommend biopsy; the reduction would be 77% if performing targeted PBx only. These findings suggest that VLR disease continues to account for a significant minority of PCa diagnoses and could be limited by targeted PBx and risk stratification calculators. Patient summary We looked at recent trends for the diagnosis of very low-risk (VLR) prostate cancer. We found that VLR cancer still seems to be frequently diagnosed despite the use of MRI (magnetic resonance imaging) scans before biopsy. The use of risk calculators to identify men who could avoid biopsy and/or biopsy only for lesions that are visible on MRI could reduce the overdiagnosis of VLR prostate cancer.

Introduction PSMA-based imaging is the preferred imaging modality recommended by NCCN guidelines for work-up of suspected recurrent or persistent prostate cancer after initial treatment with radical prostatectomy (RP) or prostate radiation and is increasingly being utilized in clinical practice. There is currently sparse data on the relative yield of PSMA PET/CT at low PSA values at biochemical recurrence. We evaluated our institutional PSMA PET/CT cohort of post-RP patients which includes 251 men with PSAs under 0.5ng/mL at the time of imaging, to identify clinical factors associated with scan positivity. Methods We retrospectively identified men treated initially with radical prostatectomy who underwent Gallium-68 or F-18 piflufolastat (DCFPyL) PSMA PET/CT for work-up of recurrence across our eleven hospital system from July 2021-March 2023. Patient characteristics, including demographic, baseline clinical, pathologic, and imaging variables, were obtained. PSMA positivity was determined based on radiology interpretation, and equivocal or likely benign lesions considered negative. Patients with history of systemic therapy or known metastatic disease (n=216), received focal therapy only (n=4), or had bladder outlet procedures only (n=3) were excluded. Clinical variables were compared with Wilcoxon Rank Test, Chi square, and Fishers’ exact test and subsequently with univariable and multivariable logistic regression. PSA was log transformed given non-normal distribution for logistic regression. Statistical significance was defined as p<0.05. Results Median PSA at time of PSMA PET/CT was 0.37 ng/mL (IQR 0.15, 1.29 ng/mL). 48.9% (210/429) of patients initially managed with RP were found to have PSMA positive finding suspicious for recurrence (Table 1). Rates of scan positivity among men with PSAs <0.5ng/mL and those <0.2ng/mL were 37% and 37% respectively.; Among patients with suspicious PSMA positive findings, 14% (29/210) had positivity within prostate bed only, 35% (74/210) had N1 disease, and 51% (107/210) had M1 disease. On multivariable analysis, age, PSA at PSMA scan, and RP Gleason Grade Group were significantly associated with PSMA positivity (Table 2). In a subset MVAs for men with PSAs under 0.5ng/mL at time of imaging, RP Gleason Grade group (p=0.02) and history of post-operative radiation (OR 2.12, 95% CI 1.13, 4, p=0.02) were associated with;scan positivity. Conclusions PET PSMA/CT for recurrence after RP identifies locoregional or metastatic disease in 49% of patients. Though men with higher PSAs (i.e. ≥ 1ng/ml) have the highest probability of harboring PSMA positive disease, roughly 40% of men with PSAs under 0.2ng/ml had positive imaging findings concerning for recurrence.; These men harbored higher grade disease at prostatectomy and were more likely to have received post-operative radiation.; Our findings suggest PET-PSMA imaging at low PSAs can be considered in selective individuals even at low PSA to inform salvage therapies.

Objective:This study aimed to evaluate the association of dynamic contrast enhancement (DCE) with clinically significant prostate cancer (csPCa, Gleason Grade Group ≥2) and compare biparametric magnetic resonance imaging (bpMRI) and multiparametric MRI (mpMRI) nomograms. Subjects/patients and methods:We identified a retrospective cohort of biopsy naïve patients who underwent pre-biopsy MRI separated by individual MRI series from 2018 to 2022. csPCa detection rates were calculated for patients with peripheral zone (PZ) lesions scored 3-5 on diffusion weighted imaging (DWI) with available DCE (annotated as - or +). bpMRI Prostate Imaging Reporting and Data System (PIRADS) (3 = 3-, 3+; 4 = 4-, 4+; 5 = 5-, 5+) and mpMRI PIRADS (3 = 3-; 4 = 3+, 4-, 4+; 5 = 5-, 5+) approaches were compared in multivariable logistic regression models. Nomograms for detection of csPCa and ≥GG3 PCa incorporating all biopsy naïve patients who underwent prostate MRI were generated based on available serum biomarkers [PHI, % free prostate-specific antigen (PSA), or total PSA] and validated with an independent cohort. Results:Patients (n = 1010) with highest PIRADS lesion in PZ were included in initial analysis with 127 (12.6%) classified as PIRADS 3+ (PIRADS 3 on bpMRI but PIRADS 4 on mpMRI). On multivariable analysis, PIRADS 3+ lesions were associated with higher csPCa rates compared to PIRADS 3- (3+ vs. 3-: OR 1.86, p = 0.024), but lower csPCa rates compared to PIRADS DWI 4 lesions (4 vs. 3+: OR 2.39, p < 0.001). csPCa rates were 19% (3-), 31% (3+), 41.5% (4-), 65.9% (4+), 62.5% (5-), and 92.3% (5+). bpMRI nomograms were non-inferior to mpMRI nomograms in the development (n = 1410) and independent validation (n = 353) cohorts. Risk calculators available at: https://rossnm1.shinyapps.io/MynMRIskCalculator/. Conclusion:While DCE positivity by itself was associated with csPCa among patients with highest PIRADS lesions in the PZ, nomogram comparisons suggest that there is no significant difference in performance of bpMRI and mpMRI. bpMRI may be considered as an alternative to mpMRI for prostate cancer evaluation in many situations.