This trial aims to clarify the relationship between carbon nanoparticles labeled lymph nodes and lymph node metastasis in different lymph node regions of colorectal cancer, and to clarify the application value of carbon nanoparticles in lymph node dissection in colorectal cancer surgery.

Inclusion Criteria:

1. a diagnosis of colorectal cancer;
2. endoscopic injection of CNP suspension preoperatively
3. planned radical resection of colorectal cancer
4. older than 18 years of age

Exclusion Criteria:

(a) emergency surgery;

The study was conducted in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine. Patient information and samples were obtained from patients undergoing radical resection of colorectal cancer in the colorectal surgery department of the hospital.