Radiation Therapy, Chemotherapy, and Soy Isoflavones in Treating Patients With Stage IIIA-IIIB Non-Small Cell Lung Cancer

PRIMARY OBJECTIVES: I. To evaluate the safety of adding oral soy isoflavone to concurrent chemotherapy and radiotherapy for the treatment of patients with unresectable stage III non-small cell lung cancer (NSCLC). OUTLINE: Patients are assigned to 1 of 2 treatment groups. GROUP I (SQUAMOUS CELL HISTOLOGY): Patients receive etoposide intravenously (IV) over 1 hour on days 1-5 and 29-33, cisplatin IV over 1 hour on days 1, 8, 29, and 36, and undergo radiation therapy (RT) 5 days a week for 6.6 weeks. Within 48 hours of initiating treatment, patients receive soy isoflavones orally (PO) daily on days 1-90. GROUP II (NON-SQUAMOUS CELL HISTOLOGY): Patients receive pemetrexed disodium IV over 10 minutes on days 1, 22, and 43 and cisplatin IV over 1 hour on days 1, 22, and 43. Patients also undergo RT and receive soy isoflavones as in Group I. After completion of study treatment, patients are followed up at 4 weeks and then every 4 months for 1 year, every 6 months for 1 year, and then yearly thereafter.