Arsenic Trioxide, Fluorouracil, and Leucovorin in Treating Patients With Stage IV Colorectal Cancer That Has Relapsed or Not Responded to Treatment

Inclusion criteria

DISEASE CHARACTERISTICS: * Histologically confirmed colorectal cancer * Stage IV disease (i.e., any T, any N, M1 disease) * Relapsed or refractory disease * Disease progressed after ≥ 2 different fluorouracil-containing chemotherapy regimens (e.g., irinotecan hydrochloride or oxaliplatin with or without bevacizumab) * Bidimensionally measurable disease * Must have tumor amenable to biopsy and be willing to undergo fine-needle aspiration * No CNS metastases PATIENT CHARACTERISTICS: * ECOG performance status 0-2 * Life expectancy \> 2 months * Platelet count \> 100,000/mm\^3 * WBC ≥ 3,000/mm\^3 * Creatinine ≤ 1.5 times upper limit of normal * Bilirubin ≤ 2 times normal * SGOT ≤ 5 times normal * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for at least 4 months after completion of study treatment * No preexisting peripheral neuropathy ≥ grade 2 * Ejection fraction ≥ 30% * Baseline QT interval \< 500 msec * No serious underlying medical illness or active infection * No underlying medical condition that could be aggravated by the treatment * No life-threatening disease unrelated to colorectal cancer * No other malignancy within the past 5 years unless currently disease-free and all therapy for the malignancy has been completed * No preexisting neurological disorder (i.e., seizure disorder) ≥ grade 3 * No cardiac disease, including any of the following: * Recurrent supraventricular arrhythmia * Any type of sustained ventricular arrhythmia or conduction block (e.g., grade II or III atrioventricular block or left bundle branch block) * Uncontrolled ischemic heart disease * History of nonsustained ventricular tachycardia * Prolonged PR intervals (i.e., 1st degree heart block) * No known hypersensitivity to arsenic trioxide or fluorouracil * No history of allergic reactions attributed to compounds of similar biologic composition to arsenic trioxide or fluorouracil PRIOR CONCURRENT THERAPY: * See Disease Characteristics * Recovered from all treatment-related toxicity * At least 4 weeks since prior chemotherapy or radiotherapy and recovered * More than 4 weeks since prior investigational drug * No other concurrent investigational or commercial anticancer agent or therapy * Concurrent local radiotherapy allowed for symptom relief (e.g., significant onset of pain after enrollment, but before beginning study therapy)