DISEASE CHARACTERISTICS: Histologically proven refractory advanced colorectal carcinoma Must have 1 of the following: Stable disease after receiving a minimum of 12 weeks of irinotecan Disease progression at any time after receiving an irinotecan containing regimen No prior chemotherapy for colorectal carcinoma during the interval between the irinotecan containing regimen and study entry Bidimensionally measurable disease Index lesions must be outside prior radiation ports Epidermal growth factor receptor (EGFr) expression (1+ or greater) must be confirmed prior to study entry Patients who have no tumor tissue available for immunohistochemical assay of EGFr testing undergo biopsy of accessible tumor No meningeal or CNS involvement by tumor