GM-CSF and Combination Chemotherapy in Treating Patients Who Are Undergoing Surgery for Stage II or Stage III Colon Cancer

OBJECTIVES: Primary * Determine the safety of neoadjuvant and adjuvant sargramostim (GM-CSF) and adjuvant chemotherapy in patients with resectable stage II or III colon cancer. * Determine the efficacy, in terms of enhanced tumor-associated macrophage response, of this regimen in these patients. Secondary * Determine overall survival and time to progression in patients treated with this regimen. OUTLINE: * Neoadjuvant therapy and surgery: Patients receive sargramostim (GM-CSF) subcutaneously (SC) once daily beginning between days -16 and -12 and continuing until day -1. Patients undergo surgical resection on day 0. Patients with stage I or IV disease are removed from the study. All other patients proceed to adjuvant chemotherapy or observation. * Adjuvant chemotherapy or observation: Patients with high-risk stage II or any stage III disease are assigned to group 1 or 2. Patients with low-risk stage II disease are assigned to group 3. * Group 1 (adjuvant therapy for high-risk stage II disease): Patients receive leucovorin calcium IV over 2 hours and fluorouracil IV on days 1, 8, 15, 22, 29 and 36. Patients also receive GM-CSF SC once daily on days 50-54. Treatment repeats every 56 days for up to 4 courses in the absence of disease progression or unacceptable toxicity. * Group 2 (adjuvant therapy for stage III disease): Patients receive adjuvant chemotherapy and GM-CSF as in group 1. Alternatively, patients may receive oxaliplatin IV over 2 hours and leucovorin calcium IV over 2 hours on day 1 and fluorouracil IV over 46 hours beginning on day 1. These patients also receive GM-CSF SC once daily on days 10-14 of every fourth course. Treatment repeats every 14 days for up to 12 courses in the absence of disease progression or unacceptable toxicity. * Group 3 (low-risk stage II disease): Patients undergo observation only every 3 months. After completion of study treatment, patients are followed periodically for survival. PROJECTED ACCRUAL: A total of 50 patients will be accrued for this study.