This is a descriptive observational study. The primary objective is to explore the EGFR gene mutation status in early stage NSCLC with adenocarcinoma histology after complete resection. The patients should be histological confirmed adenocarcinoma of the lung, have received complete resection and tested for EGFR mutation in regular medical practice.

Inclusion Criteria:

• Histological diagnosed as adenocarcinoma type of non-small cell lung cancer
• Have completed lung cancer operation
• The tumour EGFR gene mutation status test was performed as regular medical practice

Exclusion Criteria:

• Patients who disagree to participate this study

Patients from Thoracic surgery department