Preoperative Chemoradiotherapy With Raltitrexed for Intermediate or Locally Advanced Rectal Cancer in the Fit Elderly

* Inclusion Criteria: * Rectal adenocarcinoma, clinical stage II/III(T3-4 or N+, AJCC 7th), and fulfils the intermediate or locally advanced risk category standard of ESMO recal cancer clinical practice guidelines 2013. * KPS status no less than 70; Charlson comorbidity no more than 2; Fit status evaluated by CGA. * Life expectancy more than 6 months. * Hemoglobin \>= 100g/L, white blood cell \>= 3.5\*10E9/L, neutrophil \>= 1.5\*10E9/L, platelet \>= 100\*10E9/L. * Creatin normal, Total bilirubin normal, AST and AST normal, AKP normal. * Do not receive surgery ( except palliative colostomy) or chemotherapy or other anti-cancer treatment. * No previously pelvic irradiation history. * Through MDT discussion, the patient is considered to be candidate for preoperative CRT followed by surgery. * Informed consent signed. * Exclusion Criteria: * Other cancer history, except curable non-melanoma skin cancer or cervix in-situ carcinoma. * Allergy history to analog of quinazoline folate. * Active infection existed. * Severe complication, such as acute myocardial infarction in 6 months, uncontrolled diabetes ( Plasma glucose concentrations in any time of a day≥11.1mmol/L）, severe cardiac arrhythmia, etc. * Anticipate other clinical trials in four weeks before enrollment.