Abstract:Objective To explore the clinical characteristics and treatment Methods that affect the prognosis of stage Ⅰlung cancer. Methods Clinical data of stage Ⅰ lung cancer patients diagnosed and treated with radical surgical resection from 2019 to 2021 were extracted from the SEER database in the United States. Kaplan-Meier curves and log?rank tests were used for survival analysis. Univariate and multivariate Cox regression analyses were performed to identify factors affecting patient prognosis，and the impact of adjuvant therapy on postoperative overall survival was evaluated. Results A total of 5 759 patients with stage Ⅰ lung cancer were enrolled. According to the TNM staging，the proportion of stage ⅠA1 was 23.7%，stage ⅠA2 was 33.6%，stage ⅠA3 was 17.6%，and stage ⅠB was 25.1%.Among stage Ⅰ B，the proportion of patients receiving adjuvant radiotherapy was 1.7%（100/5 759），and the proportion of patients receiving adjuvant chemotherapy was 6.2%（358/5 759）. Multivariate analysis revealed that gender，histological type，TNM stage，and adjuvant radiotherapy were independent factors affecting patient prognosis（P<0.05）. Survival analysis showed that for patients with stage IB，there was no statistically significant difference in the 2?year survival rates between the group without adjuvant chemotherapy and the group with adjuvant chemotherapy（89.8%vs 90.1%，P＞0.05）. In contrast，compared to the group without adjuvant radiotherapy，adjuvant radiotherapy actually increased the risk of death，with 2?year survival rates of 71.8% and 90.6%，respectively（P< 0.05）. Conclusion The overall prognosis of stage I lung cancer after surgery is good. Gender，histological type，TNM stage，and adjuvant radiotherapy are independent factors affecting patient prognosis. Postoperative adjuvant radiotherapy and chemotherapy do not provide a survival benefit to patients and may even have adverse effects. Clinical decision-making should be cautious to avoid over treatment.