• Primary wound healing rate [ Time Frame: Within 30 days after operation ]
  the Primary wound healing rate within 30 days after operation
• CTCAE grade for complications of perineal wound [ Time Frame: Within 30 days after surgery ]
  the CTCAE grade for complications of perineal wound within 30 days after surgery
• The incidence of each complication of perineal wound [ Time Frame: Within 30 days after surgery ]
  The incidence of each complication of perineal wound within 30 days after surgery
• The rate of reoperation [ Time Frame: Within 30 days after surgery ]
  The rate of reoperation within 30 days after surgery
• The volumes of presacral drainage [ Time Frame: Within 3, 5, 7 days after surgery ]
  The volumes of presacral drainage within 3, 5, 7 days after surgery
• The volumes of presacral residual cavity hydrops [ Time Frame: 3 and 7 days postoperatively ]
  The volumes of presacral residual cavity hydrops within 3 and 7 days postoperatively
• The times of dressing change of perineal wound [ Time Frame: Within 3, 5, 7 days after surgery ]
  The times of dressing change of perineal wound within 3, 5, 7 days after surgery
• Removal time of presacral drainage tube [ Time Frame: Within 30 days after surgery ]
  Removal time of presacral drainage tube within 30 days after surgery
• Scar scores for perineal wound and evaluation of patients' overall satisfaction [ Time Frame: Within 30 days after surgery ]
  Scar scores for perineal wound and evaluation of patients' overall satisfaction within 30 days after surgery
• Hospital stay after surgery [ Time Frame: Within 30 days after surgery ]
  Hospital stay after surgery within 30 days after surgery
• The operation time [ Time Frame: Intraoperatively ]
  The operation time

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.

• Rectal Cancer
• Anal Canal Cancer

• Procedure: Traditional Closure
  Primary closure discontinuously the perineal wound of APR
• Procedure: "Cross" closure
  Two triangles of skin in the horizontal direction are excised to enlarge the skin incision, and the tumor resected. Then circumferential subcuticular suture of wound, and with tightening of the circumferential suture, the wound resembles a cross.

• Active Comparator: Traditional Closure
  Patients receive primary closure discontinuously for reconstruction of APR perineal wound
  Intervention: Procedure: Traditional Closure
• Experimental: "Cross" Closure
  Patients receive "cross" closure for reconstruction of APR perineal wound
  Intervention: Procedure: "Cross" closure

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

• First Affiliated Hospital, Sun Yat-Sen University
• First Affiliated Hospital of Jinan University
• The First Affiliated Hospital of Guangzhou Medical University
• Second Affiliated Hospital of Guangzhou Medical University
• Southern Medical University, China
• Guangdong Provincial Hospital of Traditional Chinese Medicine
• Guangzhou First People's Hospital
• The Affiliated Hospital of Guangdong Medical College
• Cancer Institute and Hospital, Chinese Academy of Medical Sciences
• Xinhua Hospital, Shanghai Jiao Tong University School of Medicine
• Meizhou People's Hospital
• Jieyang People's Hospital