Endoscopic fluorescent lymphography for gastric cancer

Abstract

Lymphography by radioisotope or dye is a well-known technique for visualizing the lymphatic drainage pattern in a neoplastic lesion and it is in use in gastric cancer. Indocyanine green (ICG) more recently has been validated in fluorescent lymphography studies and is under evaluation as a novel tracer agent in gastric cancer. The amount and dilution of ICG injected as well as the site and the time of the injection are not standardized. In our unit, endoscopic submucosal injections of ICG are made as 0.5 mg in 0.5 mL at four peritumoral sites the day before surgery (for a total of 2.0 mg in 2.0 mL). Detection instruments for ICG fluorescence are evolving. Near-infrared systems integrated into laparoscopic or robotic instruments (near-infrared fluorescence imaging) have shown the most promising results. ICG fluorescence recognizes the node that receives lymphatic flow directly from a primary tumor. This is defined as the sentinel lymph node, and it has a high predictive negative value at the cT1 stage, able to reduce the extent of gastrectomy and lymph node dissection. ICG also enhances the number of lymph nodes detected during extended lymphadenectomy for advanced gastric cancer. Nevertheless, the practical effects of ICG use in a single patient are not yet clear. Standardization of the technique and further studies are needed before fluorescent lymphography can be used extensively worldwide. Until then, current guidelines recommend an extensive lymphadenectomy as the standard approach for gastric cancer with suspected metastasis.

Keywords: Fluorescence; Gastric cancer; Indocyanine green; Lymphadenectomy; Lymphography; Sentinel lymph node.

Figure 1

Lymphatic basins, lymphatic compartments, and the strategy of sentinel node navigation surgery. l-GA: Left gastric artery basin; l-GEA: Left gastroepiploic artery basin; p-GA: Posterior gastric artery basin; r-GA: Right gastric artery basin; r-GEA: Right gastroepiploic artery basin. Citation: Kinami S, Nakamura N, Miyashita T, Kitakata H, Fushida S, Fujimura T, Iida Y, Inaki N, Ito T, Takamura H. Life prognosis of sentinel node navigation surgery for early-stage gastric cancer: Outcome of lymphatic basin dissection. World J Gastroenterol 2021; 27(46): 8010-8030. Copyright: The Authors 2021. Published by Baishideng Publishing Group Inc[38].

Figure 2

Schemas of standard gastrectomy, modified gastrectomy due to guidelines, and function-preserving curative gastrectomy with lymphatic basin dissection. Red circle: tumor; Green-colored area: extent of lymph node dissection; Orange area: extent of gastrectomy. The extent of nodal dissection in standard gastrectomy and modified gastrectomy according to the guidelines was D1+. In contrast, the extent of nodal dissection in lymphatic basin dissection was defined as D0. DG: Distal gastrectomy; GL: Japanese gastric cancer treatment guidelines; LR: Local resection; MDG: Minidistal gastrectomy; MPG: Mini-proximal gastrectomy; PG: Proximal gastrectomy; PPG: Pylorus-preserving gastrectomy; SG: Segmental gastrectomy; TG: Total gastrectomy. Citation: Kinami S, Nakamura N, Miyashita T, Kitakata H, Fushida S, Fujimura T, Iida Y, Inaki N, Ito T, Takamura H. Life prognosis of sentinel node navigation surgery for early-stage gastric cancer: Outcome of lymphatic basin dissection. World J Gastroenterol 2021; 27(46): 8010-8030. Copyright: The Authors 2021. Published by Baishideng Publishing Group Inc[38].

Figure 3

Olympus Visera Elite II near-infrared fluorescence imaging system. Copyright and courtesy of Olympus Europa SE & Co.KG, Hamburg, Germany.

Figure 4

Endoscopic submucosal indocyanine green injection in the stomach. A: Pre-pyloric neoplastic lesion; B: Appearance after two submucosal indocyanine green (ICG) injections; C: Appearance after four circumferential submucosal ICG injections.

Figure 5

Practical steps for submucosal indocyanine green injection. ICG: Indocyanine green.