Optimal Extent of Pulmonary Resection in Clinical Stage IA Non-Small Cell Lung Cancer

Inclusion Criteria:

1. The following features should be fulfilled at preoperative thin-section CT scans

   * Solitary lung nodule
   * Lesion size is 3cm or less in its maximal dimension of the entire tumor
   * The center of the tumor is located in the outer third of the lung field in either the transverse, coronal, or sagittal plane
   * Lung cancer is suspected (or NSCLC if tissue diagnosis already obtained)
2. Clinical stage T1a-bN0M0 (according to 7th AJCC staging system)
3. Absence of proximal segmental or lobar bronchial involvement.
4. NSCLC must be confirmed in intraoperative frozen section biopsies or postoperative pathologic examinations if the lesion was not histologically confirmed before operation.
5. Age ≥ 18 years and \< 75 years.
6. ECOG performance status 0-1.
7. The patient should have adequate cardiopulmonary reserve to tolerate lobectomy (ppo FEV1 \> 40% and ppo DLCO \> 40% or VO2 max \> 15ml kg-1 min-1)
8. No prior chemotherapy or thoracic radiotherapy for any malignancy.
9. No prior malignancy within 5 years from study entry (except for non-melanoma skin cancer, superficial bladder cancer, thyroid cancer or carcinoma in situ of the uterine cervix).
10. The patient agrees to participate in the study and signs the informed consent form.

Exclusion Criteria:

1. Histologic diagnosis other than NSCLC (such as small cell lung cancer, carcinoid, pulmonary lymphoma, or other benign lung disease, etc).
2. Hilar or mediastinal lymph node metastasis suspected on imaging studies (CT or PET/CT) or confirmed preoperatively by EBUS or mediastinoscopy.
3. Parietal pleura, chest wall, or mediastinal invasion is confirmed intraoperatively or postoperatively.
4. M1a disease is confirmed intraoperatively or postoperatively.
5. Bilobectomy, sleeve resection, pneumonectomy, concomitant wedge resection, or concomitant thoracic procedure (including cardiac surgery) is performed.
6. Synchronous or metachronous multiple cancers (within the past 5 years).
7. Interstitial lung disease or severe pulmonary emphysema which makes it impossible to tolerate either lobectomy or sublobar resection.
8. Active bacterial or fungal infection.
9. Uncontrolled systemic disease which makes the patient medically unfit for thoracic surgery such as unstable angina, recent myocardial infarction, congestive heart failure, or end-stage renal or liver disease.
10. Serious mental illness or psychosis.