Preoperative Chemoradiotherapy With Capecitabine Plus Irinotecan in Rectal Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the rectum * Distal margin of tumor located from 0 to 8 cm from anal verge * Tumor must be clinically resectable by surgery and R0 resection must be most likely * ECOG performance status 0-2 * No prior chemotherapy, radiotherapy to pelvis, and immunotherapy * Adequate organ functions * Patients must sign an informed consent Exclusion Criteria: * Malignant disease of the rectum other than adenocarcinoma or arisen from chronic inflammatory bowel disease * Any unresected synchronous colon cancer * Any distant metastasis * Intestinal obstruction or impending obstruction, but decompressing colostomy is permitted * Any previous or concurrent malignancy other than non-melanoma skin cancer or in situ cancer of uterine cervix * Any other morbidity or situation with contraindication for chemoradiotherapy * Patients have 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 practicing adequate contraception