The aim of this study is evaluate the effect of two different surgical treatment on lower rectal cancer after almost clinical complete response(almost-cCR). All almost clinical complete response(almost-cCRs) were entered into two groups randomly. The estimated sample size of the minimal operation group was 221, and 221 in the Mile's group. Three years' progression-free survival(PFS) and overall survival(OS) were compared.

Patients with low rectal cancer were treated with neoadjuvant radiotherapy, and two cycles of XELOX at the interval. All almost-cCRs after neoadjuvant treatment were randomly divided into minimal operation group or Mile's group. All cCRs were treated with "watch and wait". Patients after local recurrence were randomly divided into minimal operation group or Mile's group. If pathological result was pathological staging 3 after neoadjuvant therapy（ypT3） in minimal operation group or local postoperative recurrence occurred, patients need supplement of abdominoperineal resection (APR). With 3 years follow-up，the main research goals are 3 years of progression-free survival(PFS) and overall survival(OS). Secondary endpoints are side effects of chemotherapy, assessment of quality of life, surgical complications, adverse prognostic factors and so on.

Inclusion Criteria:

1. Histology is confirmed as rectal adenocarcinoma.
2. 18 to 75 years old.
3. Preoperative staging is lower than clinical stage primary tumor grade 3, regional lymph node grade 1, and metastasis was grade 0（cT3cN1M0）.
4. The anus couldn't be retained after TME.
5. Almost-cCR or cCR recurrence during observation.

Exclusion Criteria:

1. Patients were unable to tolerate the operation.
2. Preoperative stage: T4b or progress during the treatment.
3. HIV infection stage or chronic hepatitis B.
4. Active clinical severe infections.
5. Evil liquid state or decompensation of organ function.
6. Other malignant tumor history in five years.
7. Other primary carcinoma.
8. Unstable condition and incompliance of the patient