Clinical significance of lymphatic flows around pylorus identified by sentinel node mapping in patients with gastric cancer.

Abstract

12 Background: The sentinel node (SN) concept is safely applied and validated in early gastric cancer. Gastric lymph nodes are divided into five basins with the main gastric arteries. The suprapyloric lymph nodes (No. 5) and the anterosuperior lymph nodes with the common hepatic artery (No. 8a) are classified in the right gastric artery (r-GA) basin, and the subpyloric lymph nodes (No. 6) are classified in the right gastroepiploic artery (r-GEA) basin. The aim of this study is to analyze the lymphatic flows between these lymph nodes and basins. Methods: Five hundred and fourty-nine patients with cT1N0 or cT2N0 gastric cancer underwent SN mapping. We used technetium-99 tin colloid solution and blue dye as a tracer. Results: We detected SN No. 5 in 36 (6.6 %) patients. In these patients, we detected SN No. 5 with SNs that belonged to the left gastric artery (l-GA) basin (69 %), r-GA basin (14 %), and r-GEA basin (44 %). No. 6 was detected as SN significantly more frequently with SN No. 5. We detected SN No. 6 in 100 (18.2 %) patients. In these patients, we detected SN No. 6 with SNs that belonged to the l-GA basin (42 %), left gastroepiploic artery (l-GEA) basin (4 %), r-GA basin (28 %), and r-GEA basin (41 %). No. 4d, No. 5 and No. 8a were detected as SNs significantly more frequently with SN No. 6. We detected SN No. 8a in 43 (7.8 %) patients. In these patients, we detected SN No. 8a with SNs that belonged to the l-GA basin (65 %), l-GEA basin (7 %), r-GA basin (21 %), r-GEA basin (58 %), and posterior gastric artery (p-GA) basin (7 %). No. 6 and No. 9 were detected as SNs significantly more frequently with SN No. 8a. SN No. 5 and No. 8a were tend to be detected with not SNs that belonged to the r-GA basin but No. 6, and SN No. 6 was detected significantly more frequently with No. 4d, No. 5 and No. 8a. Conclusions: Our findings show that lymphatic flows exist not only between lymph nodes which are belonged to the same basin, but also between No. 5 and No.6, and No.6 and No. 8a. On the other hand, the lymphatic flows between No. 5 and No. 8a seem to be limited. Our results suggest that the lymph node dissection of No. 6 given lymphatic flows from lesser curvature side and retroperitoneal side is important for surgery of gastric cancer.