Oxaliplatin Plus Capecitabine in Treating Patients With Colorectal, Appendix, or Small Bowel Cancer

DISEASE CHARACTERISTICS: Histologically confirmed colorectal, appendiceal, or small bowel cancer Measurable disease No progression after prior capecitabine No brain metastases or leptomeningeal carcinomatosis PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm^3 Absolute neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hepatic: Bilirubin normal AST/ALT no greater than 2.5 times upper limit of normal Renal: Creatinine normal Creatinine clearance greater than 60 mL/min Cardiovascular: No symptomatic congestive heart failure No unstable angina pectoris No cardiac arrhythmia Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No sensory neuropathy No history of allergy to platinum compounds No history of allergy to antiemetics appropriate for administration during study No history of intolerance to fluorouracil No uncontrolled concurrent illness that would preclude study entry No ongoing or active infection requiring IV antibiotics HIV negative PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy and recovered Chemotherapy: See Disease Characteristics Recovered from prior chemotherapy No more than 2 prior systemic chemotherapy regimens for metastatic disease At least 6 weeks since prior nitrosoureas or mitomycin At least 8 weeks since prior eniluracil At least 3 months since prior suramin At least 4 weeks since other prior chemotherapy Endocrine therapy: Not specified Radiotherapy: Recovered from prior radiotherapy At least 2 weeks since prior radiotherapy to no more than 20% of bone marrow reserve At least 4 weeks since prior radiotherapy to at least 21% of bone marrow reserve Surgery: Recovered from prior surgery Other: At least 4 weeks since prior sorivudine or brivudine and recovered No concurrent sorivudine or brivudine No other concurrent investigational agents No other concurrent anticancer therapy or commercial agents