Sentinel node mapping guided by indocyanine green fluorescence imaging: a new method for sentinel node navigation surgery in gastrointestinal cancer.
BACKGROUND
Recently, gastrointestinal cancer has also been identified as a target for sentinel node navigation surgery (SNNS). This study is the first to determine the feasibility of sentinel node (SN) mapping guided by indocyanine green (ICG) fluorescence imaging in gastrointestinal cancer.


METHODS
Our series consisted of 22 patients with gastric cancer and 26 patients with colorectal cancer who had undergone standard surgical resection. ICG solution was injected intraoperatively into the subserosa around the tumor. Fluorescence imaging was obtained by a charge-coupled device (CCD) camera with a light-emitting diode with 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
Immediately after the ICG injection, lymphatic vessels draining the tumor and round-shaped SNs were visualized by their bright fluorescence. Even SNs that were not green in color could be easily and clearly visualized by ICG fluorescence imaging. The SN detection rate and mean number of SNs were 90.9% and 3.6 +/- 4.5 (mean +/- SD), respectively, in patients with gastric cancer, and 88.5% and 2.6 +/- 2.4, respectively, in patients with colorectal cancer. Among the patients with gastric cancer, the accuracy and false-negative rates were 88.9 and 33.3%, respectively, in patients with T(1) stage cancer, and 70.0 and 60.0%, respectively, overall, in all the patients. Among the patients with colorectal cancer, the corresponding values were 100 and 0%, respectively, in patients with T(1) stage cancer, and 82.6 and 66.7%, respectively, overall, in all the patients.


CONCLUSIONS
Our preliminary results show that ICG fluorescence imaging allows easy, highly sensitive and real-time imaging-guided SN mapping in patients with gastric or colorectal cancer. SN mapping guided by ICG fluorescence imaging could be a promising tool deserving further clinical exploration.
Kusano
Mitsuo
M
Division of General and Gastroenterological Surgery, Department of Surgery, Showa University, School of Medicine, Tokyo, Japan. surgery@med.showa-u.ac.jp
Tajima
Yusuke
Y
Yamazaki
Kimiyasu
K
Kato
Masanori
M
Watanabe
Makoto
M
Miwa
Mitsuharu
M
D000368:Aged; D015179:Colorectal Neoplasms / Q000601:surgery*; D004396:Coloring Agents; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D007208:Indocyanine Green; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D013055:Spectrophotometry, Infrared; D013274:Stomach Neoplasms / Q000601:surgery*
D004396:Coloring Agents; D005456:Fluorescent Dyes; D007208:Indocyanine Green