Patients with lung cancer who develop effusion, that is, pleural effusion, in this case already belong to stage IVA, that is, late stage, but not the most advanced late stage. The situation is more serious, indicating that the lung cancer has invaded the pleura and may spread along the pleura, making it more difficult to cure. But nowadays, with the increase of new drugs and treatments, the survival rate is increasing. In the latest TNM stage, the 5-year survival rate for this type of cases is about 10%, which means that after effective treatment, about 10 out of 100 people can live up to 5 years and achieve clinical cure. So don’t be pessimistic, even if there is pleural fluid, some patients can still survive for a long time with active treatment.