Based on the potential advantaged of preoperative chemoradiotherapy and oral fluoropyrimidine, the investigators planned a prospective randomized phase III trial which compares preoperative chemoradiotherapy and postoperative chemoradiotherapy with conventional radiation schedule and oral fluoropyrimidine to establish new standard neo-adjuvant therapy regimen in locally advanced rectal cancer.

Although there have been no confirmative data which favored preoperative chemoradiotherapy, preoperative chemoradiation have many theoretical advantage compared with postoperative one. Preoperative radiotherapy with intensive short course regimen showed significant improvement in local control even with TME, but there has been no large prospective randomized trial which proved the efficacy of preoperative chemoradiotherapy compared with the standard postoperative chemoradiotherapy. Although the final result of the German Trial may give the answer for this question, there has been no randomized controlled trial which investigated the efficacy of preoperative chemoradiotherapy using oral fluoropyrimidine which have many theoretical and clinical advantages mentioned above; the German Trial used 5-day continuous infusion of 5-FU. The investigators think that preoperative chemoradiotherapy with oral capecitabine could be new standard regimen in locally advanced rectal cancer, but this regimen must be compared with the standard postoperative chemoradiotherapy through well designed prospective randomized trial. Based on the potential advantaged of preoperative chemoradiotherapy and oral fluoropyrimidine, the investigators planned prospective randomized phase III trial which compares preoperative chemoradiotherapy and postoperative chemoradiotherapy with conventional radiation schedule and oral fluoropyrimidine to establish new standard neo-adjuvant therapy regimen in locally advanced rectal cancer.

Inclusion Criteria:

• Histologically confirmed rectal adenocarcinoma
• Tumor located below 10 cm from the anal verge
• Clinical stage T3 or potentially resectable T4, or N+ on endorectal ultrasonography (EUS) and computed tomography (CT)
• Patients must be > 18 years and < 76 years
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2
• Adequate bone marrow reserve
• Adequate renal function
• Adequate liver function
• Signed informed consent prior to randomization

Exclusion Criteria:

• Evidence of distant metastasis
• Previous history of chemotherapy or radiotherapy
• History of malignancy during recent 5 years other than skin cancer
• Pregnant or lactating woman
• Familial history of colorectal cancer