OBJECTIVES: We compared the overall survival (OS) and cancer-specific survival (CSS) of patients who received radiotherapy and surgery, respectively, in a large population. METHODS: In this study, we counted the patients diagnosed with stage IA lung adenocarcinoma in the SEER database from 2015 to 2019. We compared the overall survival (OS) and cancer-specific survival (CSS) through Kaplan Meier analysis, balanced the differences of primary data through propensity score matching (PSM), screened independent prognostic factors through Cox regression analysis, and then compared the survival differences of different treatment methods through hierarchical analysis. RESULTS: Among 11,159 patients with stage IA lung adenocarcinoma, 4254 patients chose radiotherapy alone (38.1%), and 6688 patients were finally included through the propensity score matching. The median survival time for patients with radiotherapy alone was 53 months, while the patients with surgery alone did not reach the median survival time (p <
0.001). Multivariate analysis showed that age, sex, tumor size, and household income affected the prognosis of patients. The results of the stratified analysis showed that, except in the subgroup of age ≤ 50 years, almost all subgroup analyses showed that surgical treatment achieved better results. CONCLUSIONS: Radiotherapy alone can be used as an option for patients with stage IA lung adenocarcinoma who cannot tolerate surgery, but the benefit to patients is limited, and surgical treatment may still be the best choice.