The purpose of this study is to compare the number of lymph nodes retrieved with or without the use of intraoperative fluorescence lymphography in laparoscopic radical resection of rectal cancer.

Inclusion Criteria:

• Histologically confirmed diagnosis of rectal carcinoma.
• Without multiple primary cancer.
• Without receiving neoadjuvant chemoradiotherapy.
• Sufficient organ function.
• Able to provide written informed consent.

Exclusion Criteria:

• Younger than 18 years or older than 75 years
• Synchronous or metachronous malignancy within 5 years.
• Patients with Intestinal obstruction or perforation or bleeding who require emergency surgery.
• Patients with a history of pelvic irradiation.
• ASA (American Society of Anesthesiologists) grade IV or V.
• Women who are pregnant (confirmed by serum β-Human Chorionic Gonadotropin in women of reproductive age) or breast feeding.
• Severe mental illness.
• Patients with severe emphysema, interstitial pneumonia, or ischemic heart disease who can not tolerate surgery.
• Patients who received steroid therapy within one month.
• Patients or family members misunderstand the conditions and goals of this study.