Carbon Nanoparticles for Identifying Lymph Nodes during Surgery in Colorectal Cancer: A Meta-Analysis

Abstract

Aim: To investigative the efficacy of carbon nanoparticles (CNs) to identify the lymph nodes during radical surgery in colorectal cancer. Method: The MEDLINE, EMBASE and Cochrane Library databases were searched electronically to identify the studies that compared the use of CNs (CN group) with control group in patients undergoing colorectal cancer radical surgery (from January 2009 to November 2018). The primary outcome was the number of retrieved central lymph nodes. Results: This meta-analysis identified 2 randomized controlled trials and 5 non-randomized controlled trials. Compared with the control group, the CN group resulted in an average of 7.16 more lymph nodes removed per patient (WMD = 7.16, 95% CI = 3.76 to 10.57, p < 0.01), 7.26 minutes less required for retrieving lymph nodes (WMD = -7.26, 95% CI = -13.43 to -1.09, p = 0.02), and 15.1 ml less blood loss during operation (WMD = -15.11, 95% CI = -23.15 to -7.06, p < 0.01). Although there was no significant difference in the metastatic lymph nodes between the two groups (OR = 1.02, 95% CI = 0.79 to 1.31, p = 0.87), there was 1.45 times more metastatic lymph of the stained nodes in CN group than in the control group (OR = 1.45, 95% CI = 1.13 to 1.85, p < 0.01). In addition, lymph nodes less than 5 mm were detected significantly more in the CN group than in the control group (OR = 2.15, 95% CI = 1.77 to 2.63, p < 0.01). Conclusions: The technique of CNs labeled lymph node staining in curative colorectal carcinoma is easy and effective, which can improve the retrieved number of lymph nodes, especially for nodes < 5 mm. The black stained lymph node indicate s higher risk of metastasis. Further high quality RCT is needed to verify the se conclusions.