OUTLINE: This is a randomized study. Patients are stratified by participating institution. All patients receive 2 courses of induction chemotherapy with doxorubicin, etoposide, cisplatin, and cyclophosphamide. For the first course, one group of patients receives a lower dose of cyclophosphamide than the other group. Both groups receive the same, and still lower, dose of cyclophosphamide during the second course. Beginning 1 week after the completion of induction therapy, patients receive 3 alternating courses each of radiotherapy to the mediastinal and supraclavicular areas delivered over 10-12 days and chemotherapy as in the second course of induction. Each course is initiated after a 1-week rest. Patients receive a final chemotherapy course beginning 4 weeks after the previous chemotherapy course. Patients are followed every 6 months for survival.