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

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)