Fluorescence Laparoscopic Navigation for Rectal Cancer and Sigmoid Colon Cancer

Inclusion Criteria: * Participants are aged 18-75; * Colonoscopy biopsy confirms colorectal adenocarcinoma; * Colonoscopy shows that the lower edge of the tumor is located more than 10 cm from the margin or the tumor is located in the upper rectum and sigmoid colon by imaging diagnosis; * The tumor is staged cT1-4aNxM0 by preoperative imaging; * Participants have no local complications before surgery. Exclusion Criteria: * Previous history of malignant colorectal tumor; * Multiple primary colorectal tumors; * Preoperative imaging reveals suspicious positive lymph nodes in the submesenteric artery root region (area 253); * Patients undergoing neoadjuvant therapy before surgery; * With contraindications to laparoscopic surgery; * Histoty of multiple abdominal and pelvic surgery or extensive abdominal adhesions; * Other malignancies were diagnosed within the past 5 years; * History of severe mental illness; * Pregnant or lactating women; * With uncontrolled infection before surgery.