 This is a dose escalation study which will escalate the dose of Cyberknife radiosurgery boost after external beam radiation of 45 Gy with concurrent capecitabine. The three dose levels are 4 Gy x5, 5 Gy x5 and 6 Gy x 5, with 3 patients at each dose level. Dose-limiting toxicity DLT is defined as acute grade 3 liver or intestinal toxicity or any acute grade 4 toxicity. If one patient experienced a DLT at a particular dose level, the cohort should be expanded to 6 patients. The maximum tolerated dose MTD is defined as the dose level below that which results in DLT in 2 or more of the 6 patients in each cohort. At least 5 patients should be enrolled in the cohort of 6 Gy x 5 even if none of the first 3 experienced DLT, as a means of added verification of dose tolerance, at this upper limit of dose for this study. 