OUTLINE: Patients are stratified according to relapse while receiving adjuvant therapy (relapse within 12 months of completing adjuvant therapy vs relapse while receiving adjuvant therapy). Patients receive oral doses of ethynyluracil (776C85) and fluorouracil twice daily for 28 days followed by 1 week of rest. Treatment continues every 5 weeks in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months the first year, every 4 months the second year, and every 6 months thereafter.