RATIONALE: Drugs used in chemotherapy, such as carboplatin, gemcitabine, and paclitaxel, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving chemotherapy before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed. Giving chemotherapy after surgery may kill any tumor cells that remain after surgery. It is not yet known which treatment regimen may kill more tumor cells.