Background: Lung cancer has become an important disease threatening the public health world-wide. Surgical resection is the standard of care for treating non-small cell lung cancer in early stage. For decades, pulmonary lobectomy with lymph node dissection remains the gold standard of surgical approach. Pulmonary sublobar resection with pulmonary wedge resection or segmentectomy was reserved for the patients with high surgical risk, who were unsuitable for radical surgical resection. Pulmonary sublobar resection for tumor less than three centimeter was demonstrated to associated with higher risk of tumor recurrence or worsening survival outcome as compared to that done by lobectomy. 1 However, these data was which was not necessarily applicable to patients with early lung cancer with tumor of smaller size which was more frequently detected with the health screening test by CT scan in general population now. Although several retrospective studies has demonstrated that sublobar resection can offer a similar survival outcome after surgery as compared to that done by standard lobectomy once the tumor was smaller than two centimeter 2, there is still no consensus about the role of sublobar resection for these small early lung cancer. In general, there are several factors associating with higher risk of local recurrence which should be avoided for sublobar resection, including resection margin less than 2 cm or less than the diameter of the tumor itself 3, more obvious speculation in CT image or central location which makes it difficult to obtain adequate resection margin 4,5. Therefore, sublobar resection should be applied to the patients of early lung cancer when two cm of resection margin is achievable. The central location , obvious tumor infiltration in image study or presence of lymph node metastasis should be also avoided.

Patients and methods: The study will include surgical patients from six medical centers in Taiwan. All of the patients will receive complete study about the surgical risk and tumor staging before surgery. The patients will receive general anesthesia and pulmonary resection as the standard procedures including division of pulmonary vessels and bronchus. Either VATS (Video-assisted thoracoscopic surgery) or open surgery is acceptable for the surgical approaches. The patients will be randomly assigned to lobectomy and sublobar resection groups. Two cm of resection margin will be obtained in each patient in the sublobar resection group by wedge resection or segmentectomy. Standard lymph node dissection including the pulmonary hilum and mediastinum will be done in both groups of patients. For suspicious of pulmonary hilum or mediastinal lymph node metastasis, frozen pathological examination will be requested.

Post operative care and follow-up: The patients will be transferred to intensive care unit or surgical recovery room after surgery. Medication for pain control and postoperative rehabilitation education will be given to each patient after surgery. The chest tube will be removed after daily discharge less than 100 to 200 ml without air-leakage, adequate lung expansion noted in chest X ray imaging. The patient will be discharged from the hospital one or two days after removal of the chest tube. Whole body bone scan and CT scan will be given in every 6 months at least after surgery for postoperative follow-up.