Oxaliplatin and Fluorouracil Plus Radiation Therapy in Treating Patients With Primary Esophageal or Stomach Cancer

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 drug and combining chemotherapy with radiation therapy may kill more tumor cells. PURPOSE: Phase I trial to study the effectiveness of combining oxaliplatin and fluorouracil plus radiation therapy in treating patients who have primary esophageal or stomach cancer.