RATIONALE: Drugs used in chemotherapy, such as liposome-encapsulated doxorubicin citrate and gemcitabine hydrochloride, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. It is not yet known whether liposome-encapsulated doxorubicin citrate is more effective when given together with or without gemcitabine hydrochloride in killing tumor cells.