How to reduce the complications of perineal wound after abdominoperineal resection (APR) has always been a hot topic in the medical field.To reduce the complications of perineal wound and the primary healing of perineal wound must meet the two principles of "unobstructed drainage" and " reduced tension closure".This concept is similar to the concepts of closure of enterostomy in rectal cancer patients. It was reported that use of cross-stitch closure can significantly reduce complications of closure of enterostomy. So the investigator ever used the "cross" closure to reconstruct the perineal wound of APR, which was really decrease the complications of perineal wound. However, more clinical trails was needed to confirm the conclusion.

Perineal wound problems after abdominoperineal resection (APR) for rectal cancer is reported in up to 25%～66% of patients,if the perineum does not heal primarily, the secondary wound healing may prolong hospital stay, may necessitate surgical reintervention, and often requires intensive wound care for several months. Great efforts have been taken to reduce the complications of perineal wound of APR, but the incidence of the perineal wound complications are not effectively decreased.

It was reported that one of the most important factors to determine the primary healing of perineal wound is whether the anterior sacral drainage and perineal stump drainage are sufficient and effective or not, which is similar to the concept of closure of enterostomy.

Previously, it was reported that "cross" closure is an effective method of skin closure for stoma reversal, which allows increased surgical exposure, reduces suture, smooth drainage, aesthetic healing simplifies wound care, and gives a neat cosmetic result.

Therefore, because of the success use of "cross" closure in stoma reversal to reduce the complications of perineal wound, the investigator used the "cross" closure to reconstruct the perineal wound of APR, and it really can decrease the complications of perineal wound. However, more clinical trails are needed to confirm the conclusion.

Inclusion Criteria:

1. Age: 18-75 years old;
2. ECOG performance status: 0-2;
3. Histologically confirmed rectal cancer or anal canal cancer;
4. Completely resected the primary tumor;
5. No evidence of distant metastasis;
6. Tolerable general anesthesia;
7. Total radiation dose of 45-50 Gy needed if the patient needs to receive routine segmental radiotherapy;
8. Provision of written informed consent.

Exclusion Criteria:

1. Emergency surgery required when the patients combined with acute ileus, perforation and hemorrhage;
2. Extralevator abdominoperineal resection needed;
3. American Society of Anesthesiologists (ASA) IV or V;
4. Combined with other tumors;
5. Severe mental illness;

(7)Serious cardiovascular disease, uncontrolled infections, or other serious uncontrolled concomitant disease; (8)Expectation of lateral lymph node dissection preoperatively