To evaluate lymph node dissection effect after using carbon nanoparticles in laparoscopic radical resection for rectal cancer.

Eighty patients accepted laparoscopic radical resection for rectal cancer in People′s Hospital of Beijing Daxing District from August 2016 to August 2017 were selected. They were randomly assigned as carbon nanoparticles group and control group, with forty patients in each group. Patients in carbon nanoparticles group received rejection of carbon nanoparticles into submucosal layer at the inferior border and lateral wall of tumor under enteroscopy guidance at two different times (16~18 hours before operation and during operation), and there were twenty patients at each time. Resection range was determined according to the location of tumor. Surgical specimens were delivered to department of pathology within thirty minutes after tumors were resected, and special person was assigned to assist lymph node sorting.

The amount of detecting lymph node in carbon nanoparticles group was more than control group (t=3.32, P<0.05), and positive (metastasis) rate in black dyed lymph node was higher than non-black dyed (χ²=42.76, P<0.001), the difference was statistically significant. There was no significant difference in the amount of detecting lymph node and lymph node positive (metastasis) rate between patients rejecting carbon nanoparticles sixteen~eighteen hours before operation and during operation (χ²=0.032, P>0.05).

The application of carbon nanoparticles can increase the amount of detecting lymph nodes during laparoscopic radical resection for rectal cancer, and black dyed lymph nodes which are traced by carbon nanoparticles have higher positive rate. The effect of rejecting carbon nanoparticles sixteen~eighteen hours before operation is confirmed, also it is helpful to arrange clinical work, so this technique deserves generalization and application.