CSP #2005 - Veterans Affairs Lung Cancer Surgery Or Stereotactic Radiotherapy Trial (VALOR)

Inclusion Criteria: Inclusion Criteria for Screening * Age 18 or older * Any patient with a preliminary diagnosis of stage I Non-Small Cell Lung Cancer (NSCLC), whether pathologically proven by biopsy, or highly suspicious by radiographic imaging. \[Participants will ultimately need biopsy confirmation before enrolling\] * Primary tumor size less than or equal to 5 cm by CT (may include CT images from PET/CT) * Karnofsky performance status greater than or equal to 70 * Participant has willingness and ability to provided informed consent for participation Inclusion Criteria for Randomization * Biopsy proven non-small cell lung cancer * Participant's case reviewed at multidisciplinary conference * Tumor size less than or equal to 5cm (measured on the most recent CT images available, and may include PET/CT images) * Tumor is equal to or greater than 1.0cm from the trachea, esophagus, brachial plexus, 1st bifurcation of the proximal bronchial tree, or spinal cord (measured on the most recent CT images available, and may include PET/CT images). * Mandatory FDG-PET/CT within 60 days of the randomization date (note: FDG-PET/CT may need to be repeated prior to treatment if outside of this requirement) * Mandatory pathological assessment of any lymph nodes \>10mm with a SUV \>2.5 seen on FDG- PET/CT * Mandatory biopsy of any additional concerning lesions seen on FDG-PET/CT, to make better determination that the patient is not harboring metastatic disease or a secondary primary malignancy. * Pre-operative FEV1 greater than or equal to 40% of predicted value and pre-operative DLCO greater than or equal to 40% of predicted value. * Formally evaluated and documented by a local thoracic surgeon to be medically fit to undergo a complete anatomic pulmonary resection (wedge resection not allowed) * Formally evaluated and documented by a local radiation oncologist to be eligible to receive protocol-defined stereotactic radiotherapy * Participant willingness to be randomized Exclusion Criteria: Exclusion Criteria for Screening * Previously evaluated by a local thoracic surgeon and determined to be medically inoperable * Pathological confirmation of nodal or distant metastasis * Prior history of lung cancer, not including current lesion * Prior history of thoracic surgery or lung or esophageal cancer. \[prior cardiac surgery acceptable\] * Prior history of radiotherapy to the thorax * Prior history of invasive state I-III malignancy treated with surgery, radiation therapy, chemotherapy, immunotherapy, or targeted therapy in the past 2 years, excluding prostate cancer, low-risk papillary thyroid cancer (less than or equal to 1 cm), follicular lymphoma, or chronic lymphocytic leukemia. * Prior history of IV malignancy, excluding follicular lymphoma, chronic lymphocytic leukemia, or hormone sensitive prostate cancer confined to the pelvis. * Ever diagnosed with stage IV metastatic cancer of any type * History of scleroderma * Positive Pregnancy test (for women \<61 years of age or without prior hysterectomy) Exclusion Criteria for Randomization * Pathological confirmation of nodal or metastatic disease