Patients receive cetuximab IV over 60-120 minutes on days 1 and 8. Patients also receive FOLFIRI chemotherapy comprising irinotecan hydrochloride IV over 90 minutes and leucovorin calcium IV over 2 hours on day 1 and fluorouracil IV continuously over 48 hours on days 1 and 2. Patients with 7/6 or 7/7 genotypes also receive filgrastim (G-CSF) as primary prophylaxis (patients with 6/6 genotypes receive G-CSF as secondary prophylaxis). Treatment repeats every 2 weeks for up to 8 courses in the absence of disease progression or unacceptable toxicity. Within 6 weeks after the completion of cetuximab and FOLFIRI chemotherapy, patients with responding disease undergo surgical resection of visceral metastases.