PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: More than 3 months Hematopoietic: Platelet count at least 100,000/mm3 WBC at least 2,500/mm3 Hemoglobin at least 8 g/dL (epoetin alfa allowed) Hepatic: Not specified Renal: Calcium no greater than the upper limit of normal (ULN) (bisphosphonates allowed) Creatinine no greater than 2 times ULN Other: No other prior malignancy within past 5 years except basal cell carcinoma of the skin or carcinoma in situ of the cervix No severe allergy to fish or seafood No medical condition that would interfere with intake and/or absorption of study medication (e.g., gastrectomy or major intestinal resection) No significant medical or psychiatric condition that would preclude study Not pregnant Negative pregnancy test Fertile patients must use adequate contraception