PRIOR CONCURRENT THERAPY: Biologic therapy: No primary prophylactic colony stimulating factors during the first course of therapy Chemotherapy: No prior or concurrent chemotherapy Endocrine therapy: At least 3 weeks since prior corticosteroid No chronic corticosteroid therapy (greater than 3 months) Radiotherapy: No prior radiotherapy Surgery: No prior surgery for this cancer Other: At least 30 days since prior treatment in a clinical trial No concurrent use of drugs that interact with fluorouracil (e.g., cimetidine, allopurinol, folic acid or leucovorin calcium) No other concurrent investigational drugs or anticancer treatment