The aim of the study is to evaluate whether peripheral circulating cell-free tumor DNA (cfDNA) can aid screening of recurrence after complete resection of early stage non-small cell lung cancer.

During evolution of primary tumor, tumor cells can be released into the bloodstream. It has also been shown that circulating cell-free tumor DNA (cfDNA) is released from apoptotic or necrotic tumor cells. In a study of cfDNA level after surgery in colon cancer patients, they suggested that cfDNA could detect recurrence of cancer several months earlier than the conventional follow up studies. Following several reports have suggested that cfDNA can invade host cells and alter host cell biology to cause cancer metastasis.

In this regard, we will collect from non-small cell lung cancer patients cohort who underwent curative resection, and will evaluate whether peripheral cfDNA can aid early detection of cancer recurrence. We will also study the genomic signature of cfDNA to assess the relationship between cfDNA and clinical outcome of non-small cell lung cancer patients.

Inclusion Criteria:

• All subjects need to sign the informed consent form
• All subjects have Non-small cell lung cancer which suspected on chest CT or confirmed pathologically preoperatively.
• Non-small cell lung cancer have to confirmed pathologically after operation
• Clinical stage I - IIIA by AJCC 7th staging system

Exclusion Criteria:

• Have been undergone chemotherapy or radiotherapy due to non-small call lung cancer
• Have been diagnosed any type of cancer other than cancer of skin, thyroid, uterine cervix with 3 years before enrollment
• Recurrent lung cancer
• Stage IIIB, IV by AJCC 7th staging system

non-small cell lung cancer patients who undergone curative surgery