Tumor-Treating Fields Therapy in Preventing Brain Tumors in Participants With Extensive-Stage Small Cell Lung Cancer

Inclusion Criteria: * Life expectancy of \> 3 months * Histologically proven extensive stage small cell lung carcinoma (ES-SCLC) (any T any N and any M stage) within 6 months prior to start of study treatment with the NovoTTF-200A, with a partial or complete response to at least four cycles of first-line chemotherapy * Karnofsky performance status (KPS) \> 70 * Neutrophil count \> 1.5 x 10\^9/L * Platelet count \> 100 x 10\^9/L * Bilirubin \< 1.5 x upper limit of normal (ULN) * Aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) \< 2.5 x ULN or \< 5 x ULN if patient has documented liver metastases * Serum creatinine \< 1.5 x ULN Exclusion Criteria: * Evidence of brain metastases on magnetic resonance imaging (MRI) of brain with and without contrast * History of other prior malignancy within the past 5 years except for superficial skin cancers * No severe comorbidities: * 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) * 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 trial * History of cerebrovascular accident (CVA) within 6 months prior to start of study treatment * Active infection or serious underlying medical condition that would impair the ability of the patient to receive protocol therapy * 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 * Active implantable electronic medical devices in the brain; a skull defect, a shunt, or bullet fragments * Known allergies to medical adhesives or hydrogel * Unable to operate the NovoTTF-200A device independently or with the help of a caregiver * If a female, currently pregnant, breastfeeding, or unwilling to avoid pregnancy while on study treatment * Concurrent brain directed therapy (beyond NovoTTF-200A as per protocol) * Prior clinical trial participation with brain directed therapy * Concurrent treatment clinical trials