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. Drugs such as phosphorus-32 may make the tumor cells more sensitive to radiation therapy. Chemotherapy combined with radiation therapy and phosphorus-32 may kill more tumor cells.

PURPOSE: Phase I trial to study the effectiveness of phosphorus-32 plus radiation therapy and chemotherapy in treating patients who have stage II or stage III non-small cell lung cancer.

OBJECTIVES: I. Determine the dosimetry and toxicity of interstitial phosphorus P32 colloid plus chemotherapy and radiotherapy in patients with previously untreated stage II, IIIA, or IIIB non-small cell lung cancer. II. Determine the maximum tolerated dose of phosphorus P32 colloid in these patients. III. Determine the response in patients treated with this regimen.

OUTLINE: This is a dose escalation study of phosphorus P32 colloid. Patients receive vinblastine IV on days 1, 8, 15, 22, and 29; cisplatin IV over 30-60 minutes on days 1 and 29; and phosphorus P32 colloid interstitially on day 50. Patients with tumor size less than 8.0 cm receive radiotherapy following phosphorus P32 injection 5 days a week for 6.5 weeks. Patients with tumor size greater than 8.0 cm receive radiotherapy 5 days a week for 4.5 weeks prior to phosphorus P32 injection, and for an additional 2.5 weeks following injection. Cohorts of 3 patients receive escalating doses of phosphorus P32 colloid until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 patients experience dose limiting toxicity. Patients are followed every 3 months for 2 years, and then every 6 months thereafter.

PROJECTED ACCRUAL: A total of 50 patients will be accrued for this study within 4 years.

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed, previously untreated stage II, IIIA, or IIIB non-small cell lung cancer Unresectable or inoperable disease OR Refusal of surgery Tumor reachable by CT guided needle placement Bidimensionally measurable disease by chest x-ray or CT scan No clinical/radiographic evidence of metastatic disease

PATIENT CHARACTERISTICS: Age: Over 18 Performance status: Karnofsky 60-100% Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm3 Neutrophil count at least 1,900/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9 g/dL (transfusion allowed) Hepatic: Adequate hepatic function Renal: BUN no greater than 25 mg/dL Creatinine no greater than 1.5 mg/dL Other: Less than 5% weight loss Able to receive induction chemotherapy No second malignancy within the past 5 years except skin cancer Not pregnant Negative pregnancy test Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Not specified Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to thorax Surgery: See Disease Characteristics No prior resection at primary site