DISEASE CHARACTERISTICS:

• Histologically confirmed non-hematologic malignancy
• Brain metastases or primary brain tumors are eligible provided patient is not receiving steroids or antiepileptic medications

PATIENT CHARACTERISTICS:

Age:

• 18 to 55 or 70 and over

Performance status:

• CTC 0-2

Life expectancy:

• Not specified

Hematopoietic:

• Granulocyte count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin no greater than upper limit of normal (ULN)
• SGOT no greater than ULN

Renal:

• Creatinine no greater than ULN

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• At least 4 weeks since prior chemotherapy (6 weeks for nitrosourea)
• No more than 1 prior chemotherapy regimen for metastatic disease (no limit if administered in the adjuvant setting)
• No prior camptothecin

Endocrine therapy:

• See Disease Characteristics

Radiotherapy:

• At least 4 weeks since prior radiotherapy
• No concurrent radiotherapy, including for palliation

Surgery:

• At least 4 weeks since prior major surgery