The survival of patients with stage 3a lung cancer is highly related to the surgical method, preoperative chemotherapy and postoperative chemotherapy, as follows: 1. If preoperative chemotherapy is taken 2-3 times, followed by lobectomy plus systemic lymph node dissection, and then chemotherapy is given after surgery, with a total course of 4 cycles, the patient’s survival is 38 months and the 5-year survival rate is 38.4%; 2. For patients who have 4 cycles of chemotherapy after surgery versus those who have no chemotherapy survival was 34.3 and 24.1 months, respectively, and the 5-year survival rate was 29.5% and 26%, respectively. The advantages of preoperative chemotherapy are that it can shrink the mass, reduce metastases, lower the stage of lung cancer, and improve the surgical resection rate, and the advantages of postoperative chemotherapy are that it can control potential metastases and reduce the chance of metastases during surgery, so the survival of patients with preoperative and postoperative chemotherapy is different from those without.