PurposeOur study aimed to report the annual changes in lung cancer statistics and analyze trends in sociodemographic, medical, and financial factors from 2003 to 2013 in the national database from the Korean National Health Insurance (KNHI).Materials and MethodsAmong 7,489 patients with code C34 in KNHI database, only lung cancer patients newly diagnosed after 2003 were included in the study population, for a total of 4,582 patients. Descriptive statistics were used to characterize treatment patterns and medical costs according to sociodemographic factors.ResultsApproximately 70% of subjects were male, and the mean age was 67 years. Around 46% of patients were over 70 years old, and 12% were over 80 years old. The medical costs were highest for patients younger than 60 and lowest for those over 80 years old. Surgery was more common in younger patients, while âno treatmentâ increased greatly with age. In trend analysis, the proportions of aging (p for trend < 0.001), female (p for trend=0.003), metropolitan/urban (p for trend=0.041), and lowest or highest-income patients (p for trend=0.004) increased over time, along with the prevalence of surgery as the primary treatment (p for trend < 0.001). There was also a trend with regard to change in medical costs (p for trend < 0.001), in that those of surgery and radiotherapy increased.ConclusionSurgery as a curative treatment has increased over the past decade. However, the elderly, suburban/rural residents, and low-income patients were more likely to be untreated. Therefore, active measures are required for these increasingly vulnerable groups.