Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed advanced solid tumor that is not curable by standard
therapy, including glioma and other brain tumors

- Brain metastases allowed following definitive radiotherapy

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- ECOG 0-2

Life expectancy:

- At least 8 weeks

Hematopoietic:

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

Hepatic:

- Bilirubin no greater than 1.5 mg/dL

- SGOT no greater than 4 times normal

Renal:

- Creatinine no greater than 1.5 mg/dL OR

- Creatinine clearance at least 60 mL/min

- Creatinine no greater than 2.0 mg/dL

- Calcium no greater than 10.5 mg/dL

Cardiovascular:

- No unstable angina

- No symptomatic coronary artery disease

Other:

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use 2 forms of barrier contraception AND 1 form of hormonal
contraception for at least 1 week before, during, and for at least 2 weeks after
study

- No active infection

- No other concurrent serious condition

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 4 weeks since prior biologic therapy (regional or systemic)

Chemotherapy:

- At least 4 weeks since prior chemotherapy

Endocrine therapy:

- No concurrent glucocorticoids as antiemetics

- Concurrent exogenous glucocorticoids allowed for treatment of gliomas or other brain
tumors

Radiotherapy:

- See Disease Characteristics

- At least 4 weeks since prior radiotherapy

Surgery:

- Not specified

Other:

- Dietary calcium intake of no more than 200-250 mg/day beginning 48 hours before each
course and continuing for 7 days

- No concurrent dairy products, green leafy vegetables, molasses, baking powder,
fortified cereals, and dry peas and beans