This study is to evaluate the pathologic complete response rate to pre-operative concurrent chemoradiotherapy with capecitabine plus irinotecan in resectable rectal cancer

This study is an open-label, single center, nonrandomized phase II study. Daily fractions of radiotherapy at 1.8 Gy to total of 45 Gy to tumor and draining lymph nodes and followed by a coned-down boost of 5.4 Gy to the tumor were delivered concurrently with chemotherapy.

Chemotherapy starts at day 1 of radiotherapy. Capecitabine is administered orally at a dose of 825 mg/m2 twice daily during weekdays (Monday to Friday) every week during radiotherapy. Irinotecan 40 mg/m2 is given intravenously once a week (D 1, 8, 15, 22 & 29).

Six ± 2 weeks after completion of chemoradiotherapy, curative surgery is performed.

Post-operative chemotherapy with capecitabine will be given to all patients 3-6 weeks after surgery. Capecitabine 1,250 mg/m2 twice daily on days 1-14 every 21 days will be administered for 18 weeks.

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