Comparison between end to end and side to end anastomosis after anterior resection of cancer rectum and compare the outcomes of both surgical techniques. The main outcomes were bowel functional outcomes and QoL. Bowel functional outcomes mainly included three indexes: stool frequency, urgency, incomplete defecation, and incontinence. The secondary outcomes were surgical outcomes including operative time, postoperative hospital stay, postoperative complications, reoperation, and mortality.

During the past two decades, remarkable progress has been made in the treatment of rectal cancer. The main goal of rectal surgery for malignancy is oncologic radicality in an effort to achieve the preservation of sphincters and sexual-urinary function.The introduction of circular stapling devices is largely responsible for their increasing popularity and utilization. Sphincter-saving procedures associated to partial or total mesorectal excision (TME) for the treatment of mid and distal rectal cancer have become increasingly prevalent as their safety and efficacy have been proved. Total mesorectal excision (TME) is the best available treatment for rectal cancer. With the advancement of surgical techniques, the majority of patients with mid and upper rectal cancer can undergo a sphincter-saving TME procedure. After TME, the most widely used reconstructive technique is straight coloanal anastomosis. With the advancement of surgical technique, the local recurrence rate after rectal cancer surgery has been decreased from 25-50% to 3-8%. Naturally, it is time to focus on how to improve bowel functional outcomes and quality of life (QoL) for rectal cancer patients. However, because the sigmoid colon is usually excised during surgery which decreases the storage volume of stool, there is a common problem seriously influencing the life quality of patients, including increased tool frequency, urgency and incontinence, which is termed as anterior resection syndrome (ARS). About 19-56% of patients would suffer from ARS. Thus, the demand for a technique with better functional outcomes made surgeons modify the straight anastomotic technique. Thus, another modified anastomotic technique, side-to-end anastomosis, which has been used since 1966, has gained attention. Side-to-end anastomosis usually needs a 3-5 cm-long colonic segment. Multiple studies on the literature have shown that compared with straight anastomosis, side-to-end anastomosis has advantages in bowel functional and operative outcomes.

Inclusion Criteria:

• 18 years of age to 80 years.
• Laparoscopic or open anterior resection of cancer rectum.

Exclusion Criteria:

• synchronous colorectal carcinoma
• emergency surgery
• history of colon or rectal segmental resections
• fixed rectal carcinoma who received preoperative radiotherapy

randomized comparative clinical trial