In the Low Anterior Resection of rectum for cancer, the section level of IMA and the need of SFM is still debated.

The aim of this study is to explore the different impacts of high and low ligation with peeling off vascular sheath of inferior mesenteric artery (IMA) in low anterior resection of the rectum for cancer. This study purpose to demonstrate that low IMA ligation, sparing of left colic artery (LCA) and selective SFM results in higher anastomotic leakage rate than high IMA ligation with routine SFM (with the difference of more than 5%).

Although TME is the standard curative operation for rectal cancer patients, who undergo low anterior resection (LAR) or abdominoperineal resection (APR) with a permanent colostomy, the strategy to restore the transit between colon and rectum (in case of LAR) is still debated in literature.

Several studies comparing high-tie with low-tie ligation reported a stage-specific survival benefit for high-tie, but on the other hand recent studies demonstrated that low-tie, without splenic flexure mobilization (SFM), decreases the complexity of the laparoscopic procedure and could reduces the operating time with comparable oncological outcomes.

The method of restorative surgery, after Total Mesorectal Excision (TME), largely depends on the length of the resected part of the colon, that is related to patient's anatomical features and the height of vascular ligation performed during the operation.

In attempt to perform a radical paraaortic lymph node dissection the inferior mesenteric artery (IMA) is usually ligated at its origin and the Arcade of Riolan provides bloody supply to any distal anastomosis. Unfortunately the Arcade of Riolan is an inconstant finding and sometimes (26% of cases) is mandatory to mobilize the splenic flexure to ensure a safe and tension-free anastomosis. SFM is a time-consuming component of LAR, has the additional risk of iatrogenic splenic injury and is very difficult during a laparoscopic resection.

In 2005 was demonstrated that routine SFM is not always necessary during anterior resection for rectal cancer.

A recent retrospective analysis by Mouw showed that SFM was associated with wider margins and a decreased rate of inadequate nodal staging in patients undergoing LAR.

This trial aims to demonstrate that low IMA ligation, sparing of LCA and selective SFM results in higher anastomotic leakage rate than high IMA ligation with routine SFM (with the difference of more than 5%). Furthermore this study purpose to evaluate the need to perform splenic flexure mobilization (SFM) in low ligation group and the, operation time, apical lymph nodes positive rate and short terms postoperative complication in both groups

Inclusion Criteria:

1. Histologically proven primary rectal adenocarcinoma located within 15 cm from anal verge not involving internal and/or external sphincter muscle
2. Stage I-III
3. Elective surgical treatment with TME and primary colorectal anastomosis
4. Receive or not receive neoadjuvant radio-chemotherapy
5. Overall health status according to American Society of Anesthesiologists (ASA) classification: I-III
6. Signed informed consent with agreement to attend all study visits
7. The patient is not pregnant

Exclusion Criteria:

1. Unresectable tumour, inability to perform a TME with colorectal anastomosis, inability to complete R0 resection or presence of T4b tumour necessitating a multi-organ resection
2. The patient wants to withdraw from the clinical trial
3. Loss to follow-up
4. Inability to complete all the trial procedures