This phase II trial is studying how well giving cisplatin and etoposide together with bevacizumab works in treating patients with previously untreated extensive-stage small cell lung cancer. Drugs used in chemotherapy, such as cisplatin and etoposide, work in different ways to stop tumor cells from dividing so they stop growing or die. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or deliver tumor-killing substances to them. Giving chemotherapy with a monoclonal antibody may kill more tumor cells.