Objective: In this study, we determined the possible usefulness of sentinel node (SN) mapping guided by indocyanine green (ICG) fluorescence imaging in the management of gastric cancer.
Summary background data: ICG fluorescence imaging system has recently been developed for obtaining biochemical information from living tissues.
Methods: Our series consisted of 56 patients with gastric cancer who underwent standard gastrectomy with lymphadenectomy. Two milliliters of ICG solution (0.5%) was injected into the submucosa around the tumor endoscopically before the operation or into the subserosa intraoperatively. ICG fluorescence imaging was conducted using a charge-coupled device camera with a light-emitting diode having a wavelength of 760 nm as the light source and a cut filter to filter out light with wavelengths below 820 nm as the detector.
Results: SNs were detected in 54 (96.4%) of the 56 patients, and the mean number of SNs was 7.2 +/- 7.0. Even SNs that were not green in color could be easily and clearly visualized by ICG fluorescence imaging. cT1-stage cancers were associated with a significantly higher accuracy rate (97.2% vs. 72.2%, P = 0.0127) than cT2-or cT3-stage cancers. Preoperative ICG injection was associated with a significantly higher incidence of cT1-stage cancers (87.1% vs. 40.0%, P = 0.0004), a larger mean number of SNs (9.9 +/- 7.5 vs. 4.1 +/- 5.0, P < 0.0001), a higher accuracy rate (100% vs. 73.9%, P = 0.0039), and a lower false negative rate (0% vs. 60.0%, P = 0.0345) as compared with intraoperative ICG injection.
Conclusions: This study shows that ICG fluorescence imaging allows highly sensitive image-guided intraoperative SN mapping in cases of gastric cancer. Our data suggest that SN mapping guided by ICG fluorescence imaging might be useful for predicting the metastatic status in lymph nodes in cases of gastric cancer, especially those with cT1-stage cancer.