Sunitinib as Maintenance Therapy in Treating Patients With Stage III or Stage IV Non-Small Cell Lung Cancer

OBJECTIVES: Primary * To investigate the effect of sunitinib malate on the progression-free survival of patients with stage IIIB or IV non-small cell lung cancer Secondary * To evaluate the toxicity of sunitinib when administered in the maintenance setting. * To evaluate the additional response rate to sunitinib malate when administered in the maintenance setting. * To evaluate the overall survival of patients treated with sunitinib. After completion of study treatment, patients are followed every 2 months for 1 year, every 6 months for 1 year, and periodically for 3 years.