Triplet Combination or Doublet Regimen Versus Chemoradiation as Neoadjuvant Therapy for Locally Advanced Rectal Cancer

Inclusion Criteria:

* 1）Age: 18 to 75 years old;
* 2）Histological diagnosis of rectal adenocarcinoma;
* 3）Distance form anal margin ≤ 12cm: cT3-4 or cN+ and cM0 by pelvic MR and chest + abdominal CT, estimated possible for R0 resection;
* 4）There is no signs of intestinal obstruction, or obstruction of intestinal after treating with proximal colostomy has been relieved;
* 5）Patients did not previously receive rectal surgery, chemotherapy or radiation therapy , biological treatment , except for endocrine therapy;
* 6）ECOG Performance Status :0-1
* 7）Life expectancy: more than 3 years;
* 8）sufficient bone marrow, liver and kidney function.

Exclusion Criteria:

* 1）Arrhythmia requires treatment with antiarrhythmia (except for beta-blockers or digoxin), symptomatic coronary artery disease, myocardial ischemia (myocardial infarction within the last 6 months) or congestive heart failure exceeding NYHA class II;
* 2）Severe hypertension with poor control;
* 3）History of HIV infection or active phase of chronic hepatitis B or C infection with high copy viral DNA;
* 4）Other active serious infections according to NCI-CTC version 4.0;
* 5）There is preoperative evidence for distant metastasis outside pelvis;
* 6）Cachexia and organ function decompensation
* 7）History of pelvic or abdominal radiotherapy;
* 8）Multiple primary cancer;
* 9）Patients with epilepcy requiring treatment ( steroids or antiepileptic treatment);
* 10）History of other malignant tumors within 5 years, except for cured cervical carcinoma in situ or skin basal cell carcinoma;
* 11）Drug abuse and medical, psychological or social conditions interfering patient participation in research or the evaluation of research results;
* 12）Any allergy to clinical research drugs or any drugs associated with this study;
* 13）Any unstable condition or condition that may endanger safety and compliance of patients;
* 14）Pregnancy or the lactating female without adequate contraception.