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. Combining more than one chemotherapy drug with radiation therapy may kill more tumor cells.

PURPOSE: Phase I trial to study the effectiveness of radiation therapy plus combination chemotherapy in treating patients with limited-stage small cell lung cancer.

OBJECTIVES: I. Determine the maximum tolerated dose of thoracic radiation using an accelerated boost with concurrent chemotherapy in patients with small cell lung cancer. II. Evaluate the response rate and overall survival in these patients. III. Reduce the toxic effects of treatment to esophagus and lungs.

OUTLINE: This is a radiation dose escalation study. Patients are sequentially accrued to one of four radiation dose levels. Dose level 1: Patients receive radiotherapy 5 days a week for 4 weeks followed by radiation boost given daily for 2 days, then twice daily for 3 days during week 5. (Closed to accrual 6/98) Dose level 2: Patients receive radiotherapy 5 days a week for 4 weeks followed by radiation boost given twice daily for 5 days during week 5. (Closed to accrual 9/24/99) Dose level 3: Patients receive radiotherapy 5 days a week for 18 days followed by radiation boost given in the evenings on days 19 and 20, then twice daily for 5 days during week 5. (Closed to accrual 5/5/00) Dose level 4: Patients receive radiotherapy 5 days a week for 16 days followed by radiation boost given in the evenings on days 17-20, then twice daily for 5 days during week 5. The fifth dose level is the same as the first dose level. (Closed to accrual 3/19/99) Cohorts of 5 patients are entered at each radiation dose level. If one patient experiences nonhematologic dose limiting toxicity (DLT), 5 additional patients are treated at that level. If no further DLT occurs, escalation to the next arm proceeds. Patients receive cisplatin IV plus etoposide IV on day 1 of radiotherapy and oral etoposide on days 2 and 3 every 3 weeks for 4 courses. Patients are followed every 3 months for 1 year, every 6 months for 2 years and then annually thereafter.

PROJECTED ACCRUAL: A total of 20-40 patients will be accrued for this study within 5-10 months.

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed small cell carcinoma of the lung Limited disease (stage I-IIIb but excluding T4 tumor based on malignant pleural effusion or N3 disease based on contralateral hilar or contralateral supraclavicular involvement) No pericardial or pleural effusion on chest x-ray regardless of cytology Measurable or evaluable disease Tumor must be encompassed by limited radiation therapy fields without causing severe symptomatic pulmonary dysfunction

PATIENT CHARACTERISTICS: Age: 18 to 80 Performance status: Karnofsky 70-100% Life expectancy: Greater than 6 months Hematopoietic: Absolute granulocyte count at least 1,500/mm3 Platelet count at least 150,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No symptomatic heart disease At least 6 months since prior myocardial infarction Pulmonary: See Disease Characteristics Forced expiratory volume at one second (FEV1) greater than 0.8 L No uncontrolled bronchospasm in unaffected lung Other: No other serious concurrent illness No prior or concurrent malignancy within the past 2 years except curatively treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix No other concurrent malignancy No history of uncontrolled psychiatric illness, severe head injury, chronic alcohol or drug abuse, or central nervous system disease Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy Surgery: No prior complete tumor resection