Pivotal, Open-label, Randomized Study of Radiosurgery With or Without Tumor Treating Fields (TTFields) for 1-10 Brain Metastases From Non-small Cell Lung Cancer (NSCLC).

Inclusion Criteria: 1. 18 years of age and older 2. Life expectancy of ≥ 3 months 3. New diagnosis of brain metastases from a histologically or cytologically confirmed primary or metastatic NSCLC tumor within 5 years of registration on the study. If the original histological proof of malignancy is greater than 5 years, then pathological confirmation is required (i.e.: from extra-cranial or intracranial disease). 5\. 1 inoperable brain metastasis or 2- 10 brain lesions per screening MRI, confirmed by contrast enhanced MRI amenable to SRS according to the following criteria: a. largest tumor volume \< 10 cc b. longest tumor diameter \< 3 cm c. Cumulative volume of all tumors ≤ 15 cc 6. At least one measurable disease per study protocol 7. Patients must be receiving optimal therapy for their extracranial disease according to local practice at each center. Patients may continue on systemic therapy while receiving TTFields. 8\. Able to operate the NovoTTF-200M device independently or with the help of a caregiver 9. Clinical trials prior to enrollment are allowed, as long as no brain directed therapy was included (current treatment trials are exclusionary) Exclusion Criteria: 1. Patients who are known to have somatic tumor mutations in the following genes, for which targeted agents are available that directly affect the treatment of brain metastasis: Anaplastic lymphoma kinase (ALK), epidermal growth factor receptor (EGFR), ROS-1 proto- oncogene, and proto-oncogene B-RAF 2. Patients who have a single, operable brain metastasis 3. Patients with significant edema leading to risk of brain herniation 4. Patients with midline shift \> 10mm 5. Patients with intractable seizures 6. Leptomeningeal metastases 7. Recurrent brain metastases 8. Prior WBRT for newly diagnosed brain metastases 9. Severe comorbidities: 1. Clinically-significant inadequate hematological, hepatic and renal function, defined as: Neutrophil count \< 1.5 x 10 9/L and platelet count \< 100 x 10\^9/L; bilirubin \> 1.5 x upper limit of normal (ULN); aspartate transaminase (AST) and/or alanine aminotransferase (ALT) \> 2.5 x ULN or \> 5 x ULN if patient has documented liver metastases; and serum creatinine \> 1.5 x ULN 2. History of significant cardiovascular disease unless the disease is well controlled. Significant cardiac disease includes second/ third degree heart block; significant ischemic heart disease; poorly controlled hypertension; congestive heart failure of the New York Heart Association (NYHA) Class II or worse (slight limitation of physical activity; comfortable at rest, but ordinary activity results in fatigue, palpitation or dyspnea). 3. History of arrhythmia that is symptomatic or requires treatment. Patients with atrial fibrillation or flutter controlled by medication are not excluded from participation in the study. 4. History of cerebrovascular accident (CVA) within 6 months prior to randomization or that is not stable 5. Active infection or serious underlying medical condition that would impair the ability of the patient to received protocol therapy 6. History of any psychiatric condition that might impair patient's ability to understand or comply with the requirements of the study or to provide consent 10. Implantable electronic medical devices in the brain 11. Known allergies to medical adhesives or hydrogel 12. Currently pregnant or breastfeeding 13. Planned concurrent brain directed therapy (beyond SRS and NovoTTF-200M as per protocol)