RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Radiosensitizing drugs, such as cytochlor and tetrahydrouridine, may make tumor cells more sensitive to radiation therapy. Drugs used in chemotherapy, such as cisplatin work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Combining radiosensitizers with chemotherapy and radiation therapy may kill more tumor cells.