Phase II Fixed Dose Rate Gemcitabine for Advanced or Metastatic Colorectal Cancer

Inclusion Criteria: Age >18 years Histologically proven colorectal adenocarcinoma. Locally advanced (inoperable) or metastatic colorectal carcinoma treated with at least one prior chemotherapy regimen. Progressive disease documented by CT either during or within 3 months of completion of previous chemotherapy No previous malignant disease other than non-melanotic skin cancer or carcinoma-in-situ of the uterine cervix. Unidimensional measurable disease as assessed by CT. Adequate bone marrow function; Hb >10g/dl, platelets >100 x109/l, WBC >3x109/l, Neut >1.5x109/l. Adequate liver function: Serum Bilirubin <1.5 x upper limit of normal Adequate renal function: Serum Creatinine < 0.11 mmol/L No concurrent uncontrolled medical conditions WHO performance status 0,1 or 2 Adequate contraceptive precautions, if appropriate Informed written consent Negative pregnancy test in women of child bearing age Life expectancy > 3 months Exclusion Criteria: Medical or psychiatric condition that comprise the patient's ability to take informed consent. Patients within 4 weeks of chemotherapy or radiotherapy (6 weeks for nitrosureas or mitomycin C). Previous treatment with gemcitabine. Patients with uncontrolled cerebral metastases.