Preoperative Chemoradiation Followed by Chemotherapy for Locally Advanced Rectal Cancer

Inclusion Criteria: * histologically confirmed adenocarcinoma of the rectum * distal margin of tumor located from 0 to 12 cm from anal verge measured by digital rectal examination * high risk clinical stage II or III in MRI (satisfying at least one of the followings) * circumferential resection margin \< 1 mm involved * low-lying tumor below anal verge 3 cm * T3 \> 5 mm extramural spread * T4 (involving surrounding structures or peritoneum) * cN2 (4 or more mixed signal intensity or irregularly bordered node or tumor deposit) * age 20 years or more * ECOG (Eastern Cooperative Oncology Group) performance status 0-2 * No prior chemotherapy, radiotherapy to pelvis * Adequate bone marrow function * Adequate renal function * Adequate hepatic function * patients must sign the informed consent indicating that they were aware of the investigational nature of the study in keeping with the policy of the hospital Exclusion Criteria: * malignant disease of the rectum other than adenocarcinoma or arisen from chronic inflammatory bowel disease * any unresected synchronous colon cancer * any distant metastases * intestinal obstruction or impending obstruction, but decompressing colostomy is permitted * any previous or concurrent malignancy withih 5 years other than non-melanoma skin cancer / in situ cancer of uterine cervix / early gastric cancer / thyroid cancer of low risk * any other morbidity or situation with relative contraindication for chemoradiotherapy * patients with history of significant gastric or small bowel resection, or malabsorption syndrome, or other lack of integrity of the upper gastrointestinal tract that may compromise the absorption of capecitabine * pregnant or lactating women or patients of childbearing potential not predicting adequate contraception