Celecoxib, Capecitabine, and Irinotecan in Treating Patients With Recurrent or Metastatic Colorectal Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed adenocarcinoma of the colon or rectum * Locally recurrent or metastatic disease * Measurable disease, defined as ≥ 1 measurable lesion ≥ 20 mm by conventional CT scan OR ≥ 10 mm by spiral CT scan * Bone metastases, ascites, and pleural effusion are not considered measurable disease * Measurable lesions must be located outside a previously irradiated field PATIENT CHARACTERISTICS: Performance status * SWOG 0-2 Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 Hepatic * Bilirubin normal * No Gilbert's disease Renal * Creatinine clearance \> 50 mL/min Cardiovascular * No clinically significant cardiac disease that is not well controlled by medication, including any of the following conditions: * Congestive heart failure * Symptomatic coronary artery disease * Cardiac arrhythmias * No myocardial infarction within the past year Gastrointestinal * Must have a physically intact upper gastrointestinal tract * Able to swallow tablets * No history of peptic ulcer disease or gastroesophageal reflux * No malabsorption syndrome Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No known HIV positivity * No asthma, urticaria, or allergic-type reaction after prior treatment with aspirin or other nonsteroidal anti-inflammatory drugs * No other malignancy except curatively treated cancer with no evidence of active disease * No unresolved bacterial infection requiring antibiotics * No other serious infection * No known allergy to study drugs or sulfa drugs PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * No prior chemotherapy for colorectal cancer * Patients relapsing \> 6 months after completion of prior adjuvant chemotherapy allowed * No other concurrent anticancer chemotherapy Endocrine therapy * Not specified Radiotherapy * See Disease Characteristics * At least 3 weeks since prior radiotherapy * No concurrent anticancer radiotherapy Surgery * Recovered from prior surgery * No concurrent anticancer surgery Other * Prior celecoxib for nonmalignant disorders allowed * No other concurrent cyclooxygenase-2 inhibitors or nonsteroidal anti-inflammatory drugs, including any of the following: * Rofecoxib * Ibuprofen * Naproxen * Etodolac * Oxaprozin * Diflunisal * Nabumetone * Tolmetin