No research funds were raised

This study is designed to evaluate the short-term and long-term results after single incision laparoscopic surgery for colorectal cancer（SILSC） compared with conventional laparoscopic surgery for colorectal cancer（CLSC）.

In order to improve cosmetic effect and reduce postoperative pain, single-incision laparoscopic surgery (SILS) is attracting increasing attention. SILS is considered to be the next major advance in the progress of minimally invasive surgical approaches to colorectal disease that is more feasible in generalized use. In most previous studies, SILS for colorectal cancer was feasible and short-term safe compared to conventional laparoscopic surgery (CLS) . However, there is still controversy over its potential better cosmetic effect and less postoperative pain. Moreover, the long-term oncologic outcomes are still inconclusive as only a few studies showed long-term survival data. Up to now, most studies were limited to their retrospective nature and small samples. So more studies, especially large-scale, randomized controlled trials are needed to establish the best indications for SILS for colorectal cancer.

Inclusion Criteria:

• Inclusion Criteria:
• 18 years < age ≤85 years
• Tumor located in colon and high rectum ( the lower border of the tumor is above the peritoneal reflection)
• Pathological colorectal carcinoma
• Clinically diagnosed cT1-4aN0-2 M0 lesions according to the 8th Edition of AJCC Cancer Staging Manual
• Tumor size of 5 cm or less
• ECOG score is 0-1
• ASA score is Ⅰ-Ⅲ
• Informed consent

Exclusion Criteria:

• Body mass index (BMI) >35 kg/m2
• The lower border of the tumor is located distal to the peritoneal reflection
• Pregnant woman or lactating woman
• Severe mental disease
• Previous abdominal surgery（except appendectomy and cholecystotomy）
• Emergency operation due to complication (bleeding, perforation or obstruction) caused by colorectal cancer
• Requirement of simultaneous surgery for other disease