Pemetrexed Disodium, Carboplatin, and Radiation Therapy With or Without Cetuximab in Treating Patients With Stage III Non-Small Cell Lung Cancer

OBJECTIVES: Primary * Determine the overall survival of patients with unresectable stage III non-small cell lung cancer treated with pemetrexed disodium, carboplatin, and thoracic radiotherapy with or without cetuximab. Secondary * Determine the failure-free survival and response rates in patients treated with these regimens. * Correlate epidermal growth factor receptor, erbB2, and K-ras mutations with survival and tumor response in patients treated with these regimens. OUTLINE: This is a randomized, multicenter study. * Chemoradiotherapy (courses 1-4): Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients receive pemetrexed disodium IV over 10 minutes followed by carboplatin IV over 30 minutes on days 1, 22, 43, and 64. Patients also undergo thoracic radiotherapy once daily on days 1-5, 8-12, 15-19, 22-26, 29-33, 36-40, and 43-47. * Arm II: Patients receive pemetrexed disodium, carboplatin, and thoracic radiotherapy as in arm I. Patients also receive cetuximab IV over 2 hours on day 1 and then IV over 1 hour on days 8, 15, 22, 29, 36, and 43. * Consolidation chemotherapy (courses 5-8): Beginning 3-5 weeks after completion of chemoradiotherapy, all patients receive consolidation chemotherapy comprising pemetrexed disodium alone IV over 10 minutes on day 1. Treatment repeats every 21 days for 4 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed periodically for up to 3 years. PROJECTED ACCRUAL: A total of 100 patients (50 per treatment arm) will be accrued for this study within 10-13 months.