OUTLINE: This is a dose escalation study. Patients receive oral capecitabine twice daily every twelve hours for 14 days, and IV irinotecan over 30 minutes once every 3 weeks beginning on day 1. Treatment continues for at least 2 courses in the absence of disease progression or unacceptable toxicity. The dose of capecitabine and irinotecan is escalated in cohorts of 3-6 patients until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose at which 2 of 6 patients experience dose limiting toxicity.