Can sentinel node navigation surgery reduce the extent of lymph node dissection in gastric cancer?

Our group has conducted several studies of sentinel node navigation surgery (SNNS) for the management of early gastric cancer. To determine the distribution of nodal metastases and micrometastases, we used immunohistochemical staining with anticytokeratin antibody to examine 2605 lymph nodes obtained from 108 consecutive patients with submucosal gastric cancer. When nodes were negative by routine hematoxylin and eosin (H&E) examination, micrometastases were confined to one regional lymphatic pathway near the primary tumor; however, when nodes were H&E-positive, micrometastases were distributed more widely. The wide and complicated lymphatic stream from a gastric tumor contributed to the relatively high (23%) incidence of micrometastases and the frequent occurrence of skip metastasis. In another study, we used a combination of blue dye and radiopharmaceutical to perform SNNS in 18 patients with early gastric cancer. The rate of sentinel node detection was 94%, and the average number of sentinel nodes per patient was three. Technical issues included size of particles, method of injection, accuracy of frozen section examination, and standard criteria for defining a sentinel node. SNNS for gastric cancer is a promising technique; further study of various anatomic and pathologic factors will indicate whether it can be used to determine the extent of lymphadenectomy necessary in patients with early gastric cancer.