Lobectomy-First vs. Lymphadenectomy-First for Operable NSCLC (LOFTY)

Inclusion Criteria: 1. Age from 18 to 80 years old; 2. The first clinical diagnosis before surgery was non-small cell lung cancer, including adenocarcinoma, squamous cell carcinoma, large cell carcinoma, and other unknown types; 3. Clinical stage T1-2N0-1 (cI-II): Maximum diameter of tumor \<= 5 cm and short diameter of mediastinal lymph node \<= 1cm in thin layer computed tomography (CT); 4. The patient's physical condition is able to tolerate lobectomy: (1) Goldman index 0-1; (2) Predicted forced expiratory volume in 1s (FEV1) \>= 40% and diffusing capacity of the lung for carbon monoxide (DLCO) \>= 40%; (3) Total bilirubin \<= 1.5 upper limit of normal; (4) Alanine aminotransferase (ALT)/Aspartate aminotransferase (AST) \<= 2.5 upper limit of normal; (5) Creatinine \<= 1.25 upper limit of normal and creatinine clearance rate (CCr) \>= 60 ml/min; 5. Performance status of Eastern Cooperative Oncology Group (ECOG) = 0-1; 6. All relevant examinations were completed within 28 days before the operation; 7. Patients who understand this study and have signed an approved Informed Consent. Exclusion Criteria: 1. Patients who have undergone anti-tumor therapy (radiotherapy, chemotherapy, targeted therapy, immunotherapy) before surgery; 2. Patients with previous medical history of other malignant tumors or combined with second primary cancer at the time of enrollment; 3. Patients who meet all of the following criteria are eligible for sublobar resection (segment/wedge resection): (1) Ground glass opacity (GGO) with a solid component \<= 50%; (2) The largest diameter of nodule is \<= 2 cm; (3) The nodule is located in the outer third of the lung field; 4. Patients with preoperative diagnosis of pure GGO; 5. Patients with previous medical history of unilateral thoracotomy; 6. Women who are pregnant or breastfeeding; 7. Patients with active bacterial or fungal infection that is difficult to control; 8. Patients with serious psychosis; 9. Patients with a history of severe heart disease, heart failure, myocardial infarction or angina pectoris in the past 6 months.