SABR for T1-2a N1 NSCLC

Inclusion Criteria 1. Age ≥ 18 years old at time of consent 2. Ability to provide written informed consent and HIPAA authorization 3. Pathological diagnosis of NSCLC lung cancer 4. Staging PET/CT within 45 days of consult 5. EBUS or other histologic confirmation of N1 involvement (diagnosis of lung cancer should come from the hilar \[N1\] disease) 6. T1/2a \<5cm lung primary 7. N1 disease \<5cm 8. Patient refuses surgery or deemed inoperable 9. KPS of \> 60 10. Baseline labs including CBC/differential and BMP within 45 days of consult 11. CBC/differential with adequate bone marrow function defined as follows: 1. Absolute neutrophil count (ANC) ≥ 1,500 cells/mm3 2. Platelets ≥ 100,000 cells/mm3 3. Hemoglobin ≥ 8.0 g/dl (Note: The use of transfusion or other intervention to achieve Hgb ≥ 8.0 g/dl is acceptable.) 12. Adequate renal function defined as serum creatinine within normal institutional limits or creatinine clearance must be at least 20 ml/min 13. Adequate hepatic function defined as total bilirubin ≤ 3.0 x upper limit of normal (ULN) for the institution and ALT, AST, and alkaline phosphatase ≤ 3.0 x ULN for the institution 14. If a pleural effusion is present, the following criteria must be met at registration to exclude malignant involvement (incurable M1a disease): 1. When pleural fluid is visible on both the CT scan and on a chest x-ray, a pleuracentesis is required to confirm that the pleural fluid is cytologically negative; 2. Effusions that are minimal (i.e. not visible under ultrasound guidance) and that are too small to safely tap are eligible. 15. Women of childbearing potential and male participants must practice adequate contraception throughout the study 16. Patients with post-obstructive pneumonia are eligible provided they no longer require intravenous antibiotics at registration 17. Eligible for adjuvant chemotherapy as determined by the treating medical oncologist Exclusion Criteria 1. Previous radiation therapy overlapping with current radiation target as determined by the discretion of the investigator 2. Inability to comply with treatment per investigator discretion. 3. Inability to follow standard of care follow up recommendations per investigator discretion. 4. Pregnant and breastfeeding women 5. Contra-indication to platinum-based two drug chemotherapy as determined by the treating medical oncologist 6. Patients with a history of chronic kidney disease or lactic acidosis 7. Severe, active co-morbidity, defined as follows: i. Uncontrolled neuropathy ≥ grade 2 regardless of cause ii. Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months iii. Transmural myocardial infarction within the last 6 months iv. Acute bacterial or fungal infection requiring intravenous antibiotics at the time of registration v. Chronic Obstructive Pulmonary Disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days of registration vi. Severe hepatic disease, defined as a diagnosis of Child-Pugh Class B or C hepatic disease vii. HIV positive with CD4 count \< 200 cells/microliter. Note that patients who are HIV positive are eligible, provided they are under treatment with highly active antiretroviral therapy (HAART) and have a CD4 count ≥ 200 cells/microliter within 30 days prior to registration. Note also that HIV testing is not required for eligibility for this protocol. viii. End-stage renal disease (i.e. on dialysis or dialysis has been recommended).