Irinotecan, Fluorouracil, and Leucovorin in Treating Patients With Advanced Gastrointestinal Cancer

DISEASE CHARACTERISTICS:

* Biopsy confirmed diagnosis of gastrointestinal cancer

  * Advanced, unresectable disease
* Confirmation of UGT1A1 TA indel genotype
* Measurable or evaluable (non-measurable) disease

  * Measurable disease is defined as ≥ 1 lesion that can be accurately measured (longest diameter to be recorded) as ≥ 2.0 cm with conventional techniques or as ≥ 1.0 cm with spiral CT scan

    * Clinical lesions will only be considered measurable when they are superficial (e.g., skin nodules, palpable lymph nodes)
    * Lesions on chest x-ray are acceptable as measurable lesions when they are clearly defined and surrounded by aerated lung
  * The following are considered non-measurable disease:

    * Bone lesions
    * Leptomeningeal disease
    * Ascites
    * Pleural/pericardial effusions
    * Lymphangitis cutis/ pulmonis
    * Inflammatory breast disease
    * Abdominal masses (not followed by CR scan or MRI)
    * Cystic lesions
    * All other lesions (or sites of disease), including small lesions (longest diameter \< 2.0 cm with conventional techniques or as \< 1.0 cm with spiral CT)
* No known central nervous system metastases or carcinomatous meningitis

PATIENT CHARACTERISTICS:

Inclusion criteria

* Life expectancy ≥ 12 weeks.
* ECOG performance status 0-2
* ANC ≥ 1,500/mm³
* Platelet count ≥ 100,000/mm³
* SGOT ≤ 2.5 times upper limit of normal (ULN) (≤ 5 times ULN if liver metastases)
* Total Bilirubin ≤ ULN for patients in group 3 and ≤ 2.0 times ULN for patients in groups 1 and 2
* Hemoglobin ≥ 9.0 g/dL
* Creatinine ≤ 1.5 times ULN or creatinine clearance ≥ 60 mL/min
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception for the duration of study treatment
* Willing to provide blood samples for mandatory translational studies

Exclusion criteria

* Known allergy to irinotecan hydrochloride-related agents (e.g., topotecan), 5-fluorouracil, and/or leucovorin calcium
* Active or uncontrolled infection
* Evidence of serious intercurrent illness (e.g., unstable angina, symptomatic congestive heart failure, serious uncontrolled cardiac arrhythmia)

PRIOR CONCURRENT THERAPY:

* Recovered from all toxicities
* More than 4 weeks since prior major surgery
* More than 2 weeks since completion of prior radiotherapy

  * No prior radiotherapy to \> 25% of bone marrow
* More than 2 week since prior cytotoxic chemotherapy, biologic therapy, or immunotherapy
* No concurrent sargramostim (GM-CSF)