Concurrent Once Daily Versus Twice Daily Radiotherapy for Limited Stage Small Cell Lung Cancer

RATIONALE: Drugs used in chemotherapy, such as cisplatin and etoposide, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. It is not yet known which schedule of radiation therapy is more effective when given together with chemotherapy in treating small cell lung cancer. PURPOSE: This randomized phase III trial is studying two different schedules of radiation therapy to compare how well they work when given together with cisplatin and etoposide in treating patients with limited stage small cell lung cancer.