[Effect of injecting activated carbon ultramicroparticles around the gastric tumor on staining lymph node]

To observe the effect of injecting activated carbon ultramicroparticles around the gastric tumor before or during operation on staining lymph nodes and guiding the lymphadenectomy of gastric cancer.

Forty-three cases of gastric cancer received activated carbon (AC) ultramicroparticles around the tumor by submucosal endoscopic injection 1 approximately 6 days before the operation and/or intraoperative subserosal injection (AC group), whereas 82 cases of gastric cancer without the injection were used as control group. The number of dissected lymph nodes, number of black-stained lymph nodes and its relation to the injection time, metastasis of lymph nodes, and the side effect of the procedure were analyzed.

The average numbers of resected lymph nodes were 34 +/- 13 in the AC group, significantly higher than that in the control group (16 +/- 9, P < 0.05). The dissected N(2) lymph nodes in the AC group was 25 +/- 9, significantly higher than that in the control group (8 +/- 4, P < 0.05). The total ratio of black-stained lymph node was 60.3% in general, 71.3% for the N1 lymph nodes and 56.3% for the N(2) lymph nodes in the AC group. Satisfactory effect of black staining of lymph nodes could be seen 2 days after local gastric tissue injection of activated carbon ultramicroparticles. The metastasis rate was 67.4% in the AC group, not significantly different from that in the control group (63.4%, P > 0.05). In the patients of AC group the metastasis rate of black-stained lymph node was 26.8%, significantly higher than that of the unstained lymph nodes (3.3%) and higher than that of the control group (18.4%). No serious side effect happened after the activated carbon ultramicroparticles injection in local gastric tissue.

Local injection of activated carbon ultramicroparticles around the tumor is an effective, easy and safe procedure to guide gastric cancer lymphadenectomy.