Safety of Pentoxifylline and Vitamin E With Stereotactic Ablative Radiotherapy (SABR) in Non-small Cell Lung Cancers

3.1 Inclusion Criteria: - Eligibility Criteria 3.1.1 Age \>/= 18 years 3.1.2 ECOG performance status 0-1 3.1.3 Histologically proven diagnosis of a prior thoracic malignancy treated with thoracic external beam radiotherapy with or without systemic chemotherapy 3.1.4 Pathologic or clinical diagnosis of a new or loco-regional recurrent lung malignancy. A reasonable attempt should be made to make a pathologic diagnosis of malignancy (ie. bronchoscopy, CT guided lung biopsy) * Loco-regional is defined as recurrence within the region of the primary tumor or adjacent draining lymph node regions. * The new lesion or loco-regional recurrence must be within or adjacent to the previously irradiated treatment volume. 3.1.5 Imaging as follows: * CT scan of the chest with IV contrast within 8 weeks of registration * Whole body PET scan within 8 weeks of registration 3.1.6 Pulmonary function test (PFTs), including diffusion capacity within 8 weeks of registration 3.1.7 Negative serum pregnancy test within 2 weeks prior to registration for women of childbearing potential. 3.1.6 Women of childbearing potential and male participants who are sexually active must agree to use a medically effective means of birth control 3.1.7 Patients must provide study specific informed consent prior to study entry. Exclusion Criteria: \- 3.2 Exclusion Criteria 3.2.1. No previously reported thoracic radiotherapy 3.2.2. FEV1 \<20% predicted and/or DLCO \<20% predicted 3.2.2. Pregnant women or lactating women 3.2.3 Chemotherapy within 4 weeks of the initiation of SABR 3.2.4 Plans to administer systemic chemotherapy overlapping with radiotherapy