This is a clinical trial from Eastern Cooperative Thoracic Oncology Project (ECTOP), numbered as ECTOP-1012. The goal of this clinical trial is to confirm the theraputic effect of segmentectomy for ground glass-dominant invasive lung cancer with size of 2-3cm. The main questions it aims to answer are:

• The 5-year disease-free survival of patients having ground glass-dominant invasive lung cancer with size of 2-3cm;
• The post-operative lung function tests after receiving segmentectomy. Participants will receive segmentectomy as the surgical procedure.

Inclusion Criteria:

• Patients who sign the informed consent form and are willing to complete the study according to the plan;
• Aged from 18 to 80 years old;
• ECOG equals 0 or 1;
• Not receiving lung cancer surgery before;
• Confirmed to be invasive lung adenocarcinoma intraoperatively or postoperatively;
• Ground glass-dominant lung nodules
• Consolidation-to-tumor ratio (CTR) ranges from 0 to 0.5, and tumor size ranges from 2 to 3cm;
• cN0 without distant metastasis;
• Tumors could be completely resected assed by surgeons;
• Not receiving chemotherapy or radiotherapy before.

Exclusion Criteria:

• CTR is not 0-0.5, or size is not 2-3cm;
• Tumors could not be completely resected assed by surgeons;
• Not lung adenocarcinoma diagnosed cytologically or pathologically;
• Receiving lung cancer surgery before;
• Receiving radiotherapy or chemotherapy.