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

To estimate an upper bound for the proportion of newly diagnosed men 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. 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-eligible was defined as the union of low risk, potentially low risk, and favorable intermediate risk. Group differences in proportions were evaluated using χ 2 tests; temporal trend was assessed with a Cochran–Armitage trend test. Primary analyses used complete cases. 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) (p<0.001). Across 17 districts, eligibility ranged from 16.9% (Chungbuk) to 29.3% (Gyeonggi) (p<0.001). Urban areas (dong) had higher eligibility than rural areas (eup/myeon): 26.4% vs 20.5% (p<0.001). 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.