Risk factors for atypical lymph node metastasis in gastric cancer

Lymph node (LN) metastasis is very important for the prognosis of gastric cancer, and topics surrounding the amount of LN dissection during surgery remain controversial. Nodal metastasis of gastric cancer cells is relatively more aggressive than other cancers and removal is necessary even for micrometastasis nodes [1]. Currently, D2 dissection is accepted as the gold standard of gastric cancer treatment. However, D1 dissection is also performed in early gastric cancer (EGC) without LN metastasis in Korea and Japan [2,3]. Endoscopic mucosal resection, endoscopic submucosal dissection, and sentinel node navigation surgery (SNNS) have been attempted to preserve gastric function and improve quality of life according to the recent minimal invasive tendency [4-8]. Gastric cancer has a relatively complex multidirectional lymphatic flow, and the rate of skip metastasis is not low, making it difficult to apply SNNS in the treatment of gastric cancer [9-11]. Therefore, if risk factors related to the possibility of atypical LN metastasis, such as skip metastasis, are identified, it is helpful to set an indication of minimally invasive surgery. To date, skip metastases have been studied several times; however, to the best of our knowledge, studies on transversal metastases are rare [12,13]. There were also only a few studies on atypical LN metastasis in advanced gastric cancer (AGC). The purpose of this study was to determine the distribution of atypical LN metastasis according to tumor location and depth. Original Article Korean Journal of Clinical Oncology 2019;15:100-105 https://doi.org/10.14216/kjco.19018 pISSN 1738-8082 ∙ eISSN 2288-4084