Contrast-free MRI-first screening in young asymptomatic men: Prostate characteristics and cancer detection rates

Early-onset prostate cancer is becoming increasingly prevalent, and MRI-first strategies are gaining interest as a potential screening tool. However, MRI characteristics of the prostate in younger men remain underexplored. This study aimed to characterize prostate MRI features in a young, asymptomatic male cohort undergoing contrast-free biparametric MRI for prostate cancer screening, to determine the detection rate of clinically significant prostate cancer, and to identify clinical and imaging predictors of clinically significant disease.

A total of 659 prostate MRIs were acquired; after excluding men who declined biopsy, 641 participants formed the final cohort. Peripheral-zone signal patterns on T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and apparent diffusion coefficient (ADC) maps were assessed by two blinded radiologists. PI-RADS scores were assigned independently. Men with PI-RADS ≥ 4 were offered targeted MRI-TRUS fusion biopsy (PI-RADS 3 in case of PSAD ≥ 0.16). Multivariable logistic regression was performed to identify independent predictors of csPCa.

Median PSA 1.02 ng/mL (IQR 0.58-2.03) and PSA density (PSAD) 0.03 ng/mL/mL (IQR 0.02-0.05). The most common peripheral-zone appearance was heterogeneous T2 hypointensity (74.7%), homogeneous DWI hyperintensity (59.4%), and homogeneous ADC hypointensity (66.1%). PI-RADS distribution was: 0.5% PI-RADS 1, 81.1% PI-RADS 2, 14.2% PI-RADS 3, 3.6% PI-RADS 4, and 0.6% PI-RADS 5. Forty-one men (6.4%) underwent biopsy, yielding 5 ciPCa, 23 csPCa, and 13 negative results, corresponding to csPCa in 3.6% of the entire cohort. In multivariable analysis, PSAD ≥ 0.15 ng/mL/mL, PI-RADS 4-5, and family history were independently associated with csPCa (all p < 0.01).

Contrast-free bpMRI effectively characterizes prostate morphology in younger men and identifies csPCa at an early stage. PSAD, PI-RADS category, and family history significantly enhance risk stratification, supporting the integration of bpMRI-based approaches into future MRI-first screening strategies for younger, asymptomatic populations.