Abstract
<title>Abstract</title> <p>Prostate biopsy practice has evolved substantially with the introduction of pre-biopsy magnetic resonance imaging (MRI), but long-term regional changes remain incompletely characterized. We analyzed annual prefecture-wide aggregate data from Yamanashi, Japan, for fiscal years 2004–2024 and 2,929 institutional biopsy procedures performed at the University of Yamanashi Hospital during fiscal years 2011–2024. Temporal trends were assessed using linear and grouped quasibinomial regression, and policy-period associations were evaluated after adjustment for fiscal year. Across Yamanashi Prefecture, 20,192 biopsy procedures were reported, with 10,365 cancers detected. Annual biopsy volume decreased by 21.1 procedures per fiscal year (95% confidence interval [CI], − 29.5 to − 12.8; P < 0.001), whereas the cancer detection rate increased from 39.4% to 69.5% (odds ratio [OR] per fiscal year, 1.069; 95% CI, 1.061–1.077; P < 0.001). Institutionally, pre-biopsy MRI utilization increased from 10.2% to 97.7%, while overall and clinically significant prostate cancer detection increased significantly; Grade Group 1 detection did not. After temporal-trend adjustment, a significant post-policy level difference was observed only for MRI utilization (OR, 9.295; 95% CI, 3.562–24.257; P < 0.001). These findings suggest increasingly selective biopsy practice, while improvements in cancer detection likely reflect multiple evolving diagnostic factors rather than MRI policy alone.</p>