Lymphatic Dissemination and the Role of Sentinel Lymph Node Biopsy in Early Gastric Cancer

Abstract

(N2) lymph node stations. The applicability of SNLB in gastric cancer has been studied in recent years in an effort to accurately predict metastasis to (non)regional lymph nodes. The ultimate goal is to identify patients who truly need a lymphadenectomy and to identify patients in whom lymphadenectomy can be omitted. Obviously, patients with suspicious or proven lymph node metastases are not eligible for SNLB and a routine D2 lymphadenectomy is deployed. Also in patients with advanced tumours (T3 and more), SNLB does not seem appropriate [2] . These patients already have a high probability of having firstor second-tier lymph node metastases. Moreover, in advanced tumours, original lymphatic drainage routes might be obstructed or altered, resulting a lower accuracy of the SNLB. In ECG the prevalence of lymph node metastasis is relatively low. Lymph node metastases are found in approximately 3% of mucosal EGC. In submucosal ECG, lymph node metastases are found in approximately 20% but with a wide range from 10 to 64% [3–5] . In addition, approximately 5% of lymph node metastases in submucosal EGC are located in second-tier lymph nodes, mainly nodal stations 7, 8a and 9 [6, 7] . The article of Dong et al. [1] confirms the low prevalence of lymph node metastases (6 of 111 patients, 5%) in mucosal EGC and the relatively high prevalence of lymph node metastases (58 of 144 patients, 40%) in submucosal ECG in 255 retrospecGastric cancer remains one of the most important malignant diseases with significant geographical, ethnic, and socioeconomic differences in distribution. Early gastric cancer (EGC), defined as cancer limited to the mucosa or submucosa with or without lymph node metastases, is rarely seen in the Western world and often a chance finding. In Asia the incidence is much higher mainly due to mass screening programs in areas where there continues to be a high incidence of gastric cancer. Treatment of EGC has evolved in the last decades from invasive surgical approaches towards endoscopic and other minimally invasive techniques. Involvement of regional lymph nodes in patients with EGC largely determines the treatment of choice. In this edition of Digestive Surgery, Dong et al. [1] report on the prevalence of lymph node metastases and the application of the sentinel lymph node biopsy (SNLB) in EGC. In breast cancer and melanoma surgery the sentinel lymph node procedure has proven to be a valuable tool in lymph node mapping with a sensitivity of more than 95%. When the SNLB is negative, lymphadenectomy can safely be omitted. Hence, SNLB is now routine practice in these cancer types. In gastric cancer, lymph node status is one of the most important prognostic factors. The extent of gastrectomy and lymphadenectomy is largely based on the likelihood of lymph node metastases to first(N1) and second-tier Received: January 8, 2012 Accepted: January 8, 2012 Published online: April 24, 2012