From literature review, circulating tumor cell was demonstrated its possible role in disease relapse. It was rare nit could be identified in all lung cancer patients. In addition, circulating tumor cell usual aggregate to form circulating tumor micro-emboli and caused distant metastases. Therefore, circulating tumor cell could play a role in detect disease relapse and appropriate treatment could be given more earlier and further prolong patients' survival. However, the detail clinical significance of circulating tumor still remains unknown. The aim of this study was evaluate the clinical significance, including present timing, numbers, and correlation to disease relapse, of circulating tumor cell in lung cancer patients. The investigators want to clarify the clinical significance between circulating tumor cell and clinical presentation of lung cancer in order to establish new prediction model and improve lung cancer patients' survival.

Study subject:

Inclusion criteria 1. Patients with clinical stage 1 to 3a non-small lung cancer 2. Patients with a resectable suspicious pulmonary lesion which is difficult for pre-operation tissue prove or refused for pre-operation biopsy 3. Received curative intended tumor resection Exclusion criteria

1. Small cell lung cancer component which identified in pathology
2. Patients who presented as stage IIIb or IV
3. Not received curative intended surgery due to multi-comorbidities
4. Patients who presented in tumor seeding or positive resection in pathology confirmation
5. Patients who received neoadjuvant therapy

Data collection:

medical record review and blood sampling for circulating tumor cell purification

Timing of blood sampling:

a.Pre-operation, post-operation, post-operation day 1, post-operation day 3 b regular OPD surveillance (3 month-interval) for 3 years

Blood sampling: 20 ml blood that withdrawn from a peripheral vein

Circulating tumor cell purification: two-step procedure

1. cell isolation: centrifugation, isolated karyocyte > 10 micrometer
2. negative selection: wash out RBC, WBC depletion
3. positive selection: purify circulating tumor cell (karyocyte which presented CD 45 negative, Epi-CAM positive, diameter greater 10 micrometer

Result analysis:

Combine the medical record to analyze the relationship between circulating tumor cells and disease relapse

Inclusion Criteria:

1. Non-small cell lung cancer patients with stage I to III

2. Patients with resectable suspicious pulmonary malignant lesion

   1. no pre-operation diagnosis ( patients refused biopsy or difficult for biopsy)
   2. image survey showed clinical stage I to III

Exclusion Criteria:

1. Final pathology coexisted with small cell lung cancer component
2. Patients who presented as stage IIIb or IV.
3. Not received curative intended surgery due to multi-comorbidities.
4. Patients who presented in tumor seeding or positive resection in the final pathology
5. Patients who received neoadjuvant therapy.

Patients with a resectable malignant or suspicious malignant pulmonary lesion