Preoperative CRT With Temozolomide Plus Capecitabine in Rectal Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the rectum * Tumor located within 12cm of anal verge * Clinical stage of T3-4 or N+ by rectal MRI with or without endorectal ultrasound * Available tumor samples before study treatment (fresh or paraffin-embedded) for immunohistochemistry (IHC) and methylation-specific PCR (MSP) to investigate MGMT expression and hypermethylation * Male or female aged over 20 years * Be ambulatory and have an Eastern Cooperative Oncology Group (ECOG) performance status 0-1. * No prior systemic treatment (chemotherapy, immunotherapy) or radiation therapy * Adequate major organ functions as following: * Be willing and able to comply with the protocol for the duration of the study. * Give written informed consent prior to study-specific screening procedures, with the understanding that the patient has the right to withdraw from the study at any time, without prejudice. Exclusion Criteria: * Histology other than adenocarcinoma or tumor arising from inflammatory bowel disease * Inadequate tumor sample for MGMT IHC or MSP * Any evidence of systemic metastasis * Unresected synchronous colon cancer * Intestinal obstructions or impending intestinal obstruction, but bypass surgery (colostomy or ileostomy) is permitted before study treatment * Uncontrolled or severe cardiovascular disease * Serious concurrent infection or nonmalignant illness that is uncontrolled or whose control may be jeopardized by complications of study therapy. * O…