This study is designed primarily to establish efficacy and estimate resource utilization. The short-term hypothesis is that the dose of capecitabine (825 mg/m2 twice/day 5 days per week) during the course of radiation therapy is efficacious in locally advanced, non-metastatic rectosigmoid carcinoma and will improve resectability. The long-term working hypothesis is that if 3-D CRT is combined with the potentiating and additive effect of capecitabine one hopes to see improved and durable tumor response and survival with acceptable toxicity. In addition, it is expected that the simplicity of using an oral agent (capecitabine) will be associated with reduced cost and resource utilization.