Long-Term Risk of Clinically Significant Prostate Cancer in Biopsy-Negative Patients With Baseline Biparametric Prostate MRI

Abstract

Background: The long-term prevalence of clinically significant prostate cancer (csPCa) in patients with initial negative prostate biopsy is unknown.

Purpose: To investigate the rate of csPCa of men with initial negative biopsy.

Study type: Retrospective analysis of prospectively collected data.

Population: A total of 197 men (mean age 63 years [SD ±6.98, range 29-79]) without csPCa on initial biopsy and available baseline biparametric prostate MRI (bpMRI).

Field strength/sequence: 3.0 T, turbo spin-echo T2-weighted (axial and sagittal) and three sets of diffusion-weighted imaging using single-shot spin-echo planar imaging (5 b-values 0-500 seconds/mm²; 2 b-values 0 and 1500 seconds/mm², and 2 b-values 0 and 2000 seconds/mm²).

Assessment: BpMRI was read using Prostate Imaging Reporting Data System (PI-RADS) v2.1. Systematic or targeted biopsy results served as reference standard.

Statistical tests: Continuous variables were compared using Kruskal-Wallis rank sum test. Categorical variables were compared using either Fisher's exact test or Pearson's chi-square test. Uni- and multivariate regression odds ratios (95% confidence interval) were used to study factors affecting csPCa being diagnosed during follow-up. Time to diagnosis of csPCa is calculated using the Kaplan-Meier method.

Results: Of 197 men, 74 (38%), 57 (29%), and 66 (34%) presented with PI-RADS 1-2, 3, and 4-5 findings in the baseline bpMRI. During the median follow-up of 52 months, 8.1%, 5.3%, and 18.2% of these men were diagnosed with csPCa, respectively. Baseline PI-RADS finding was the only factor that associated with csPCa found during the follow-up.

Data conclusion: Baseline bpMRI with PI-RADS scores 1-3 and initial biopsies negative of csPCa had low rate of csPCa during follow-up, which supports more conservative follow-up for them but further research with longer follow-up is warranted.

Level of evidence: 3 TECHNICAL EFFICACY: Stage 2.