This study is one of Eastern Cooperative Thoracic Oncology Projects (ECTOP-1016). The goal of this clinical trial is to confirm the concordance rate between intra-operative frozen section pathological diagnosis and post-operative paraffin embedded pathological diagnosis, and use this result to guide surgical treatment for early stage (cT1N0M0) lung adenocarcinomas.

Inclusion Criteria:

• Patients who sign the informed consent form and are willing to complete the study according to the study protocol;
• No previous history of cancer or pulmonary surgery;
• Solitary lesions or multiple lesions with only one not manifesting as pure ground-glass opacity (GGO) on CT scan;
• Peripheral clinical T1N0M0 patients that are eligible for surgery;
• Non-small cell lung cancer is pathologically diagnosed before or at surgery;
• No radiation therapy or chemotherapy before surgery.

Exclusion Criteria:

• Patients with clinical stages other than T1N0M0;
• The lesion cannot be completely resected;
• Previous history of cancer;
• Patients having received radiation therapy or chemotherapy.

Clinical stage T1N0M0 lung adenocarcinoma patients who are going to undergo surgical resection.