Preoperative Concurrent Chemotherapy and Intensity Modulated Radiotherapy (IMRT) in Locally Advanced Rectal Cancer

Inclusion Criteria: * Pathologically proven diagnosis of adenocarcinoma of the rectum * Clinically determined to be stage T3 or T4,N0-N2, and M0 -staged by MRI or transrectal ultrasound of the rectum * Patients who are medically operable and who have resectable adenocarcinoma of the rectum at least \<15cm from the anal verge * Adequate liver/renal and haematological function. * Eastern Cooperative Oncology Group (ECOG) performance 0-2 * Age ≥ 18 years * Full blood count obtained within 2 weeks prior to registration on study, with adequate bone marrow function defined as follows: * Absolute neutrophil count (ANC) ≥ 1,800 cells/mm3 * Platelets ≥ 100,000 cells/mm3 * Haemoglobin ≥ 8.0 g/dl * Serum creatinine within normal institutional limits or creatinine clearance ≥ 50 ml/min * Bilirubin within normal institutional limits * AST and ALT \< 2.5 x the IULN * Patient must sign study specific informed consent prior to study entry Exclusion Criteria: Prior invasive malignancy (except non-melanomatous skin cancer) unless disease free for a minimum of 3 years * Prior systemic chemotherapy for colorectal cancer; note that prior chemotherapy for a different cancer is allowable. * Prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields * Severe, active comorbidity, defined as follows: * Unstable angina and/or congestive heart failure requiring hospitalization within the last 12 months * Transmural myocardial infarction within the last 6 months * Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects * Acquired immune deficiency syndrome (AIDS) based upon current CDC definition; note, however, that HIV testing is not required for entry into this protocol. * Evidence of uncontrolled seizures, central nervous system disorders, or psychiatric disability judged by the investigator to be clinically significant, precluding informed consent, or interfering with compliance of oral drug intake. * Known, existing uncontrolled coagulopathy. Patients on therapeutic anticoagulation may be enrolled provided that they have been clinically stable on anti-coagulation for at least 2 weeks. * Major surgery within 28 days of study enrollment (other than diverting colostomy) * Pregnancy or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception; this exclusion is necessary because the treatment involved in this study may be significantly teratogenic * Prior allergic reaction to capecitabine * Any evidence of distant metastases (M1) * A synchronous primary colon carcinoma * Extension of malignant disease into the anal canal * Lack of physical integrity of the gastrointestinal tract (i.e., severe Crohn's disease that results in * malabsorption; significant bowel resection that would make one concerned about the absorption of capecitabine) or malabsorption syndrome that would preclude feasibility of oral chemotherapy (capecitabine) * Participation in any investigational drug study within 28 days of study enrollment