This is a clinical trial from Eastern Cooperative Thoracic Oncology Project (ECTOP), numbered as ECTOP-1018. The goal of this clinical trial is to confirm the theraputic effect of selective lymph node dissection for cT1N0M0 invasive non-small cell lung cancer with CTR>0.5 located in the apical segment. The main questions it aims to answer are:

The 5-year overall survival of patients having cT1N0M0 invasive non-small cell lung cancer with CTR>0.5 located in the apical segment; The post-operative lymph node metastasis and recurrence-free survival. Participants will receive selective lymph node dissection as the surgical procedure.

Inclusion Criteria:

1. Patients who sign the informed consent form and are willing to complete the study according to the plan;
2. Aged from 18 to 80 years old;
3. ECOG equals 0 or 1;
4. Not receiving lung cancer surgery before;
5. Resectable peripheral cT1N0M0 tumors with CTR>0.5 located in the apical segment;
6. Non-lepidic predominant invasive NSCLC dignosed by frozen section;
7. Not receiving chemotherapy or radiotherapy before.

Exclusion Criteria:

1. Not cT1N0M0;
2. Nodules not located in the apical segment or CTR≤0.5;
3. Pre-invasive lung adenocarcinoma, lepidic predominant adenocarcinoma, or not lung adenocarcinoma diagnosed cytologically or pathologically;
4. Receiving lung cancer surgery before;
5. Receiving radiotherapy or chemotherapy.