Safety Trial of Antimicrobial Therapy and Precision Radiation Therapy in Patients With Oligoprogressive Non-small Cell Lung Cancer

Randomized Pilot Inclusion

* Patients planned to receive Stereotactic Body Radiotherapy (SBRT) to a biopsy-proven or clinically-suspected NSCLC
* Age \>18 years' old
* Patient capable of giving informed consent

Randomized Pilot Exclusion

* Use of antibiotics, antifungal, antivirals or antiparasitics during the 4 weeks prior to registration
* Active infection with oral temperature \>100°F
* Use of corticosteroids, methotrexate or immunosuppressive drugs during the 4 weeks prior to registration
* Use of chemotherapy during the 4 weeks prior to radiotherapy or during radiotherapy. Chemotherapy cannot begin before the collection of the 30-day post treatment sample (S4).
* Documented history of HIV, HBV or HCV
* Active uncontrolled gastrointestinal disorders such as inflammatory bowel disease, moderate/severe irritable bowel syndrome, persistent, infectious gastroenteritis, colitis or gastritis, persistent or chronic diarrhea of unknown etiology, Clostridium Difficile infection (within 2 years of lung cancer diagnosis) or Helicobacter Pylori infection (untreated)
* Major surgery of the GI tract, with the exception of cholecystectomy and appendectomy, in the past five years. Any major bowel resection at any time
* Patients on anti-diarrheal medications
* Patients on probiotics

Safety Trial Inclusion

* Patients planned to receive precision hypofractionated radiation (SBRT or an ablative dose of radiation is used if SBRT is not appropriate or if insurance does not approve - i.e. \> 30 Gy in 10 fraction equivalent) to all sites of oligoprogressive NSCLC who progressed after 1st line systemic therapy for metastatic disease which included immunotherapy or a tyrosine kinase inhibitors (TKI) for NSCLC
* The number of sites of progression are \< 5 sites.
* Age \>18 years' old
* Patient capable of giving informed consent

Safety Trial Exclusion

* Evidence of untreated CNS or leptomeningeal disease
* Use of antibiotics, antifungal, antivirals or antiparasitics during the 4 weeks prior to registration
* Active infection with oral temperature \>100°F
* Use of oral corticosteroids, methotrexate or immunosuppressive drugs during the 4 weeks prior to registration
* Use of chemotherapy during the 4 weeks prior to radiotherapy or during radiotherapy. Chemotherapy cannot begin before the collection of the 30-day post treatment sample (S3).
* Documented history of HIV, HBV or HCV
* Patients on daily anti-diarrheal medications
* Use of probiotics during the 4 weeks prior to radiotherapy or during radiotherapy