Inclusion Criteria:

   - Newly diagnosed, histologically proven (or strongly suspected, see below) T1-T2aN0M0
   (Stage IA-IB) non-small cell lung cancer (NSCLC), with maximum tumor diameter =< 5 cm
   under consideration for stereotactic ablative body radiotherapy (SABR) as definitive
   primary treatment

   - Pathologic confirmation of NSCLC diagnosis is recommended whenever possible; this will
   generally be accomplished using computed tomography (CT) guided or bronchoscopic
   biopsies; if pathologic confirmation is not possible, a target lesion must be a non
   calcified pulmonary nodule that is present on at least 2 imaging studies (can include
   simulation scan); the nodule must have increased in size or proportion of solid
   component on CT and/or show increased fluorodeoxyglucose (FDG) uptake on positron
   emission tomography (PET) over at least 2 imaging studies

   - No history of prior radiotherapy overlapping with high dose region of planned SABR
   course

   - No prior receipt of systemic treatment (chemotherapy, targeted therapy, or
   immunotherapy) for the lesion under consideration of treatment

   - No uncontrolled, inter-current or recent illness that in the investigator's opinion
   precludes participation in the study, including those undergoing therapy for a
   separate invasive malignancy

   - Able to give informed consent

   - Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 to 2

Exclusion Criteria:

   - No significant anemia (hemoglobin below 9.0 g/dL) or neutropenia (absolute neutrophil
   count [ANC] < 1000/mm^3)

   - No prior history of lung resection on ipsilateral side

   - No prior history of multifocal adenocarcinoma in situ (ie, classic or pure
   bronchioloalveolar carcinoma)

   - No prior history of idiopathic pulmonary fibrosis

   - No prior history of keratoacanthoma (well differentiated squamous cell skin cancer
   variant, often centrally ulcerated); history of basal cell cancer is allowed

   - No contraindication to receiving radiotherapy and no known allergy to components of
   fresolimumab

   - No pregnant or breastfeeding women; men or women of child bearing potential must agree
   to use an acceptable method of birth control (hormonal or barrier method of birth
   control; abstinence) to avoid pregnancy for at least 90 days after last study
   treatment (radiation or fresolimumab); all women of child bearing potential (last
   menstrual period within the previous 12 months and not surgically sterile) will be
   tested for pregnancy at pre-entry