This is a randomized phase Ⅱ study, in which S-1 is used in combination with leucovorin in elderly patients with advanced colorectal cancer as first-line treatment,comparing with sLV5FU2 therapy. The aim of this study is to determine the efficacy and safety of S-1/LV in elderly patients in the first-line setting. The other secondary endpoints are progression free survival,overall survival, and quality of life are also evaluated.
