Effect of ligation sequence of the inferior mesenteric artery and vein on circulating tumor cells and survival in laparoscopic rectal cancer surgery: a prospective, multicenter, randomized controlled study (ARVECTS)

Several studies have demonstrated that the presence of circulating tumor cells (CTCs) in the peripheral blood can be a surrogate biomarker to predict recurrence and prognosis of rectal cancer. CTCs are released from the primary tumor into the bloodstream and have the potential to spread to distant sites and develop into micro-metastatic deposits. Numerous studies have demonstrated that surgical manipulation could promote the dissemination of tumor cells into the circulation. Theoretically, the potential risk of tumor cell dissemination can theoretically be minimized if the effluent vein was ligated first. However, there is no regulation in the current guidelines on the sequence of ligation of the inferior mesenteric artery and vein during rectal cancer surgery owing to a lack of sufficient evidence. This multi-center randomized controlled trial is to investigate effect of ligation sequence of the inferior mesenteric artery and vein on circulating tumor cells and survival in laparoscopic rectal cancer surgery

Inclusion Criteria:

1. Age: 18-75 years;
2. Histopathologically confirmed as rectal adenocarcinoma(tumor located within 15 cm from the anal verge at colonoscopy);
3. Patients with a stage I-III rectal cancer eligible for surgery and R0 resection is expected, patients with pelvic lateral lymph nodes metastasis are ineligible;
4. ECOG score: 0-1;
5. ASA score: I/II/III;
6. Laparoscopic surgery;
7. Informed consent.

Exclusion Criteria:

1. Patients who have received preoperative treatment (such as preoperative radiotherapy and chemotherapy);
2. Receiving transanal total mesorectal excision (taTME), specimen extraction through natural lumen (NOSES) ;
3. Recurrent rectal cancer;
4. Simultaneous or metachronous colorectal cancer;
5. Malignant tumors of other organs in the past 5 years or at the same time;
6. The results of preoperative physical examination and imaging examination showed that: (1) the tumor involved the surrounding organs and required combined organ resection; (2) distant metastasis; (3) could not be resected at R0;
7. Pregnant or lactating women;
8. Patients with severe mental disorder;
9. It is not suitable for patients undergoing laparoscopic surgery (such as extensive adhesion caused by previous abdominal surgery or inability to tolerate artificial pneumoperitoneum);
10. History of unstable angina pectoris or myocardial infarction in the past 6 months;
11. Have a history of cerebrovascular accident in the past 6 months;
12. Systemic administration of corticosteroids within 1 month before enrollment;
13. Taking folic acid related drugs within half a year before operation.
14. Severe cardiac insufficiency (FEV1<50% of predicted values);
15. Emergency surgery.