There is no such term as diffuse lung cancer in clinical practice, which mostly refers to multiple cancer foci in both lungs. Generally, the prognosis is poor, which is affected by the stage of tumor and physical condition of patients. 1. Tumor stage: Generally speaking, the later the tumor stage is, the worse the prognosis is. The five-year survival rate of patients with stage I lung adenocarcinoma is about 70%, the five-year survival rate of patients with stage II lung adenocarcinoma is about 40%, and the five-year survival rate of patients with stage IV lung adenocarcinoma is even less than 5%. 2. Physical condition of patients: Generally speaking, older patients with more underlying diseases will have worse prognosis than younger patients with fewer underlying diseases. If diagnosed with lung adenocarcinoma, patients should actively cooperate with doctors for treatment, maintain a healthy lifestyle and a good mindset, all of which can help improve the prognosis.