DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed chondrosarcoma

* Histologic grade G2 or G3
* Recurrent and unresectable OR metastatic disease
* Measurable disease by x-ray, scan, ultrasound, or physical examination
* No known CNS metastases

PATIENT CHARACTERISTICS:

Age

* 18 and over

Performance status

* Zubrod 0-2

Life expectancy

* Not specified

Hematopoietic

* Absolute neutrophil count ≥ 1,500/mm\^3
* Platelet count ≥ 100,000/mm\^3

Hepatic

* Bilirubin \< 1.5 times upper limit of normal (ULN)
* SGOT or SGPT \< 2.5 times ULN (5 times ULN if liver metastases are present)

Renal

* Creatinine clearance \> 45 mL/min

Other

* Not pregnant or nursing
* Fertile patients must use effective contraception
* Able to swallow oral medication
* No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or adequately treated stage I or II cancer in complete remission

PRIOR CONCURRENT THERAPY:

Biologic therapy

* More than 28 days since prior biologic therapy for this malignancy

Chemotherapy

* More than 28 days since prior chemotherapy for this malignancy

Endocrine therapy

* Not specified

Radiotherapy

* At least 60 days since prior radiotherapy to the target lesion\*
* No concurrent radiotherapy NOTE: \*Target lesion must have demonstrated disease progression after completion of therapy

Surgery

* At least 21 days since prior surgery and recovered

Other

* More than 28 days since prior investigational drugs for this malignancy
* At least 60 days since prior embolization or radiofrequency ablation to the target lesion\*
* No more than 2 prior treatment regimens for this malignancy
* No concurrent antiretroviral therapy for HIV-positive patients NOTE: \*Target lesion must have demonstrated disease progression after completion of therapy