RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving combination chemotherapy before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed. Radiation therapy uses high-energy x-rays to kill tumor cells. Drugs such as gemcitabine and cisplatin may make tumor cells more sensitive to radiation therapy. Giving combination chemotherapy before surgery or radiation therapy may kill more tumor cells.