OBJECTIVE: The aim of the study is to demonstrate that the intracorporeal resection and anastomosis in left-sided colon cancer, sigma and upper rectum, is not inferior to extracoprporeal resection and anastomosis, in terms of anastomotic leakage.

BACKGROUND: Due to the recent events of a pandemic respiratory disease secondary to infection by SARS-CoV-2 virus or coronavirus 19 (COVID19), surgeons have been forced to adapt our surgical procedures in order to minimize exposure to the virus as much as possible.

Based on the recommendations in case of surgery in patients with highly contagious viral diseases, the latest studies suggest minimally invasive accesses to minimize the risk of contagion. One of the proposed measures is the performance of intracorporeal anastomoses. Therefore, given the extensive experience of our center in minimally invasive surgery and studies on the validation of intracorporeal anastomosis techniques in both laparoscopic surgery of the right colon and rectum (TaTME), and the study of advantages that they can provide to the patient, our intention is to apply it to surgery on the left colon, sigma and upper rectum. Our hypothesis is that exteriorization of the colon through an accessory incision increases the risk of tension at the mesocolon level, thus increasing the risk of vascular deficit at the level of the staple area and it may increase the rate of anastomotic leakage. In this sense, studies that validate a standard technique of intracorporeal anastomosis in left colon surgery and that demonstrate its benefit with respect to extracorporeal anastomosis are lacking. We intend to describe a new intracorporeal anastomosis technique (ICA) that is feasible and safe for the patient and that can be applied universally. Once the ICA technique is established, it will allow us to determine its non-inferiority compared to the standard technique performed up to now with extracorporeal anastomosis.

METHODS: All consecutive patients with left-sided, sigma and upper rectum adenocarcinoma will be included into a prospective cohort and treated by laparoscopy with totally intracorporeal resection and anastomosis. They will be compared with a retrospective cohort of consecutive patients of identical characteristics treated by laparoscopy with extracorporeal resection and anastomosis, in the immediate chronological period.

HYPOTHESIS Resection of the left colon / sigmoid with intracorporeal colorectal TT anastomosis is safe and not inferior to that performed extracorporeally. With the benefits of reduced intraoperative dissection, traction on the mesenteries, reduced vascular compromise of the anastomosis, a smaller incision size and being able to choose its location.

Main Aim:

The objective of this study is to demonstrate that colorectal mechanical end-to-end intracorporeal anastomosis is not inferior to extracorporeal approach in terms of anastomotic dehiscence.

Secondary Aims:

• To demonstrate the reproducibility of the colorectal mechanical end-to-end intracorporeal anastomosis technique in terms of reconversion, anastomotic dehiscence, organo-cavitary infection, and other postoperative complications.
• To determine the benefits that the IC anastomosis technique can bring to patients with obesity.
• To determine the benefits that the IC anastomosis technique can provide in terms of postoperative complications, hospital stay, and size of the accessory incision.
• To determine the benefit of the application of indocyanine green to determine the point of resection and anastomosis.

STUDY DESIGN

Comparative, single-center, controlled non-inferiority cohort study of resection and mechanical end-to-end intracorporeal anastomosis in left colon, sigmoid, and upper rectum surgery (prospective cohort) versus the standard technique of extracorporeal laparoscopic surgery (retrospective cohort).

SUBJECTS OF THE STUDY

In group 1 or control (retrospective cohort): patients diagnosed with adenocarcinoma of the left colon, sigmoid or upper rectum who meet the inclusion criteria Operated on surgically by our unit, collected in our database, by laparoscopic oncological surgery applying the conventional extracorporeal anastomosis technique.

In group 2 or case (prospective cohort): patients diagnosed with adenocarcinoma of the left colon, sigmoid or upper rectum, that meet the inclusion criteria, with an oncological surgical indication with a laparoscopic approach since July 2020, to which the resection and intracoporeal anastomosis technique will be applied.

Inclusion Criteria:

• Left Colonic Adenocarcinoma. Location of the tumor in the left colon, sigma or high rectum (with the anastomosis performed above the peritoneal reflection). Non-metastatic stage. Scheduled oncological surgery with curative intention operated on with laparoscopic surgery with resection technique and intracorporeal anastomosis. Over 18 years

Exclusion Criteria:

• Other tumor locations. Non-adenocarcinoma tumors. Synchronous tumors. T4 tumor stage and stage IV of TNM classification. ASA IV (American Society of Anesthesiologists). Non-optimal nutritional study (preoperative albumin ≤3.4 g / dl). Do not sign informed consent. Pregnant patients. Diagnosis of another type of neoplasm with active disease. Liver cirrhosis, Chronic kidney failure on dialysis treatment, patients with stent bridge to elective surgery.

In group 1 or control (retrospective cohort): patients diagnosed with adenocarcinoma of the left colon, sigmoid or upper rectum who meet the inclusion criteria Operated on surgically by our unit, collected in our database, by laparoscopic oncological surgery applying the conventional extracorporeal anastomosis technique.

In group 2 or case (prospective cohort): patients diagnosed with adenocarcinoma of the left colon, sigmoid or upper rectum, that meet the inclusion criteria, with an oncological surgical indication with a laparoscopic approach since July 2020, to which the resection and intracoporeal anastomosis technique will be applied.