Detection of Sentinel Nodes in Gastric Cancer by Indocyanine Green Fluorescence Imaging

Background/Aims: The sentinel nodes (SN) are the first nodes to receive lymphatic drainage from a primary tumor. The SN concept is useful to avoid unnecessary resection in gastric cancer. Indocyanine green (ICG) fluorescence imaging is a new method for detecting SN and we herein examined the usefulness of this technology. Methodology: The subjects comprised 39 cT1-2N0 gastric cancer patients who underwent standard surgery from 2006 to 2009. 0.8mL ICG (1%) was injected into the submucosa around the tumor two days preoperatively (Preop group) or intraoperatively (Intraop group) by endoscopy. SN were postoperatively identified by fluorescence imaging and the accuracy of this method compared to the dye method was investigated for 76 patients treated from 2000-2004. Results: SN was detected as fluorescence-positive nodes (FN) and the mean FN number was 9.3 +/- 6.4. The specificity was 100% and all metastatic lymph nodes were detected as FN in three patients. The mean number of FNs was 7.2 in the preop group and 12.5 in the postop group (p=0.032). The FN method was associated with a low false negative rate, same as the dye method. Conclusions: SN mapping using ICG fluorescence imaging has high accuracy and this compound can be injected preoperatively to detect SN.