Whether lung adenocarcinoma is serious in early stage depends on the actual situation. If it can be diagnosed and treated in time in early stage, it is usually not serious, while if it is not found in time in early stage, it is more serious. Lung adenocarcinoma is a common type of lung cancer, which mainly originates from bronchial mucosa epithelium. To determine whether lung adenocarcinoma is serious in early stage needs to be based on the actual situation, and cannot be generalized, there are obvious individual differences. If lung adenocarcinoma can be diagnosed in time in its early stage, and actively treated and strengthened in daily life management, it is usually not serious. However, if lung adenocarcinoma is not diagnosed in time in the early stage, leading to further progression of the disease, it is relatively more serious. Clinically, “5-year survival rate” is often used to roughly assess the survival of tumor patients. Studies show that the 5-year survival rate of lung adenocarcinoma in early stage is about 70%, and if it is in stage IA, the 5-year survival rate is higher than 80%, and the median survival period can be close to 10 years. All in all, patients with early stage of lung adenocarcinoma need to go to the hospital in time, actively cooperate with doctors for treatment, and follow up regularly to avoid delaying their condition.