To investigate the accuracy of fluorescence angiography technique IMA classification and the impact of lymph node mapping technique on the dissection of No. 253 lymph nodes.

Multiple studies, including randomized controlled trials (RCTs), have demonstrated that lymph node imaging techniques can effectively increase the number of harvested lymph nodes in gastric and colorectal cancer surgeries . However, there remains a scarcity of research specifically focused on the surgical procedure of fluorescent-guided clearance of No. 253 lymph nodes. Most existing studies have been retrospective analyses, and the need for prospective studies is evident. Further clinical research is crucial to explore the successful application of fluorescence lymph node imaging combined with indocyanine green (ICG) fluorescence angiography and its multifunctional fusion. To address this gap, investigators plan to conduct a randomized controlled trial comparing the outcomes between the use of ICG Fluorescence lymph node Imaging combined with Fluorescence angiography (FIFA group) and conventional techniques (non-ICG group) in laparoscopic rectal cancer surgery. Specifically, investigators focus will be on the preservation of the left colic artery (LCA) and the clearance of No. 253 lymph nodes. The primary objectives of our study are to simplify surgical procedures, enhance surgical safety, and provide substantial evidence for the further promotion and adoption of this technique.

Inclusion Criteria:

• Patients aged between 18 and 75 years
• Colonoscopic biopsy confirmed colorectal adenocarcinoma
• The tumor was located in the rectum or upper rectum, and the surgical method was Dxion
• No local complications before operation (no obstruction, incomplete obstruction, no massive active bleeding, no perforation, abscess formation, no local invasion)
• Preoperative imaging diagnosis was cT1-4aNxM0
• The hematopoietic functions of heart, lung, liver, kidney and bone marrow meet the requirements of surgery and anesthesia
• Sign the informed consent form

Exclusion Criteria:

• Previous surgical history of malignant colorectal tumors
• The surgical methods were combined abdominoperineal resection, Hartman operation and ISR operation
• There are contraindication of laparoscopic surgery, such as severe cardiopulmonary insufficiency
• Patients who have undergone multiple abdominal and pelvic surgeries or extensive abdominal adhesion
• Patients with intestinal obstruction, intestinal perforation, intestinal bleeding and other emergency operations
• ASA grade ≥IV and/or ECOG physical status score ≥2 points
• Patients with severe liver and kidney function, cardiopulmonary function, coagulation dysfunction or combined with serious underlying diseases can not tolerate surgery
• Have a history of serious mental illness
• Patients with uncontrolled infection before operation