OUTLINE: This is a randomized study. Patients are stratified according to disease stage (stage IIIB vs stage IV without CNS involvement vs stage IV with CNS involvement vs recurrent/progressive disease post surgery and/or radiotherapy). Patients are randomized to one of two treatment arms. Arm I: Patients receive gemcitabine IV over 30 minutes immediately followed by irinotecan IV over 90 minutes on days 1 and 8. Arm II: Patients receive gemcitabine IV over 30 minutes immediately followed by docetaxel IV over 60 minutes on days 1 and 8. Treatment repeats every 3 weeks in the absence of disease progression or unacceptable toxicity. Patients achieving partial or complete response or stable disease receive treatment for least 6 courses and for 2 additional courses beyond the maximum response, and then at the investigator's discretion. Patients are followed every 3 months for 1 year, every 6 months for 2 years, and then annually thereafter until disease progression or death.