Active surveillance could apply to one-quarter of Korean prostate cancer cases: Insights from a 27,075-patient cohort.

Background: The aims of this study were to estimate an upper bound for the proportion of men newly diagnosed with prostate cancer in Korea who could be managed with active surveillance (AS) when favorable intermediate-risk disease is included and to describe variation in AS eligibility by calendar year, administrative district, and residential setting. Materials and methods: We analyzed biopsy-confirmed prostate cancer diagnosed in 2010, 2012, 2014, 2016, 2018, and 2020 across 51 general hospitals nationwide. Risk was classified using routinely collected clinicopathologic variables (prostate-specific antigen, clinical T stage, Gleason grade group, and biopsy core involvement); AS eligibility was defined as the union of low risk, potentially low risk, and favorable intermediate risk. Group differences in proportions were evaluated using χ Results: Among 27,075 men (37.9% of nationally reported cases in the indexed years), 1,476 (5.45%) were low risk, 1,082 (4.00%) potentially low risk, 4,028 (14.88%) favorable intermediate risk, 5,880 (21.72%) unfavorable intermediate risk, and 14,609 (53.94%) high risk. Overall, 6,586 (24.3%) were AS-eligible. By year, AS eligibility decreased from 27.6% (2010) to 22.0% (2020) ( Conclusions: Approximately one-quarter of newly diagnosed men in Korea appear potentially eligible for AS under a maximized definition that includes favorable intermediate-risk disease. AS eligibility differed significantly by year, region, and residential setting.