 You will receive radiation therapy once a day for 5 days in a row Monday-Friday for 5 weeks and three days a total of 28 treatments. You will take the chemotherapy drug capecitabine by mouth twice a day on each of the days that you receive radiation therapy. These pills will not be taken on Saturday and Sunday. You must not take cimetidine, and must be off of coumadin for at least one week and sorivudine and brivudine for at least four weeks before starting capecitabine and while taking capecitabine. 