RATIONALE: Drugs used in chemotherapy, such as arsenic trioxide and dexamethasone, work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Sometimes when chemotherapy is given, it does not stop the growth of cancer cells. The cancer is said to be resistant to chemotherapy. Giving ascorbic acid may reduce drug resistance and allow the cancer cells to be killed. Thalidomide may stop the growth of cancer cells by blocking blood flow to the cancer. Giving arsenic trioxide together with ascorbic acid, dexamethasone, and thalidomide may kill more cancer cells.