Carboplatin With or Without Gemcitabine in Treating Patients With Advanced Ovarian Epithelial Cancer That Has Not Responded to Previous Chemotherapy

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one drug may kill more tumor cells. It is not yet known if carboplatin is more effective with or without gemcitabine for ovarian epithelial cancer. PURPOSE: Randomized phase III trial to compare the effectiveness of carboplatin with or without gemcitabine in treating patients who have advanced ovarian epithelial cancer that has not responded to previous chemotherapy.