PurposeWe investigated changing patterns of primary treatment in Korean men with prostate cancer (PC) and impact of sociodemographic factors on treatment choice from a nationwide cohort over 10 years.Materials and MethodsWe conducted a cohort study of a 2% nationwide random sample of Korean National Health Insurance. A total of 1,382 patients who had undergone active treatments for newly diagnosed PC between 2003 and 2013 were included. Time trends in primary treatment of PC, including radical surgery, radiation therapy (RT), and androgen deprivation therapy (ADT) were analyzed.ResultsTotal number of patients undergoing active treatments increased significantly (162%). Surgery cases showed the most significant increase, from 22.4% in 2003 to 45.4% in 2013, while the relative proportion of ADT showed a tendency to decrease from 60.3% in 2003 to 45.4% in 2013, and the relative proportion of RT was variable over 10 years (from 7.2% to 18.4%). While treatment patterns differed significantly according to age (p < 0.001) and income classes (p=0.014), there were differences in primary treatment according to residential area. In multinomial logistic regression analysis, older patients showed significant association with ADT or RT compared to surgery, while patients with higher income showed significant association with surgery.ConclusionTreatment pattern in Korean PC patients has changed remarkably over the last 10 years. Sociodemographic factors do affect the primary treatment choice. Our results will be valuable in overviewing changing patterns of primary treatment in Korean PC patients and planning future health policy for PC.