Endoscopic Ultrasound Predict the Sensitivity of Stage II / III Rectal Cancer Preoperative Concurrent Chemoradiotherapy

Inclusion Criteria: * pathologically confirmed rectal cancer, preoperative stage II / III (T3-4N0 or T1-4N + M0). * tumor distance from anus less than 12 cm. * KPS score not less than 70 * can be tolerated chemotherapy and radiotherapy. * pelvic who had no history of radiation therapy. * Non-allergic history of fluorouracil or platinum-based chemotherapy drugs. * a full understanding of the study, the ability to complete all of the treatment plan, follow up the conditions and sign the informed consent. Exclusion Criteria: * other malignancy (past or at the same time), does not include curable non-melanoma skin cancer and cervical carcinoma in situ; does not include resectable primary colon cancer (synchronous or metachronous). * pregnant or lactating patients. * fertility but did not use contraceptive measures. * existing active infection. * merge serious complications, can not tolerate the treatment, such as 6 months of myocardial infarction, mental illness, uncontrollable diabetes or uncontrollable hypertension or hypotension. * concurrent treatment with other anticancer drugs. * can not complete treatment or follow-up.