Combination Chemotherapy and Computer-Planned Radiation Therapy in Treating Patients With Unresectable Stage III Non-Small Cell Lung Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Radiation therapy uses high-energy x-rays to damage tumor cells. Computer systems that allow doctors to create a 3-dimensional picture of the tumor to plan treatment may result in more effective radiation therapy. It is not yet known which chemotherapy and/or radiation therapy regimen is more effective in treating non-small cell lung cancer. PURPOSE: Randomized phase II trial to compare the effectiveness of different combination chemotherapy regimens and 3-dimensional radiation therapy in treating patients who have unresectable stage III non-small cell lung cancer.