Cohorts of 3-6 patients receive escalating doses of irinotecan hydrochloride, oxaliplatin, and capecitabine until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. Once the MTD is determined, an additional 6-10 patients (for a total of 12 patients) receive treatment at that dose.