Prostate cancer detection in routine clinical practice: a large cohort study in Japan.

Population-based organized prostate-specific antigen (PSA) screening is implemented in 80% of Japanese municipalities; however, Shiga Prefecture remains a unique exception without such a systematic program. This study characterized the longitudinal clinical features and treatment patterns in this opportunistic testing environment using data from 1716 patients diagnosed via prostate biopsy in 2012, 2017, and 2022. While median PSA levels remained stable (10.40-11.43 ng/mL), median age at diagnosis increased from 72 to 74 years. Over the decade, the incidence of International Society of Urological Pathology Grade Group 1 and cT1c stages decreased significantly (p < 0.001), with nearly 90% of cases being cT2 or higher in 2022. Risk classification showed a decrease in low-risk cases and a rise in high-risk cases. Regarding treatment, radical prostatectomy rates remained stable at approximately 25%, whereas the overall use of active surveillance (AS) increased from 1 to 9%. Notably, among low-risk patients, AS adoption rose markedly from 2.3% in 2012 to 68% in 2022. While clinical practices have evolved to successfully minimize unnecessary invasive intervention, these findings suggest that clinical progress alone cannot fully compensate for the lack of organized efforts to improve early detection.