AB10. Predictive factors for lymph node metastasis and feasibility of endoscopic treatment for early gastric cancer

Backgrounds and objective: Gastric cancer is the fourth most common malignant cancer diagnosis worldwide following lung cancer, breast cancer and colorectal cancer, and the second leading cause of malignancy-related death following lung cancer. The advanced gastric cancer has a poor prognosis whereas early gastric cancer (EGC) has a far more favorable prognosis with a 5-year survival rate exceeding 90% after curative resection. Lymph node metastasis (LNM) is the most important factor for assessment of prognosis of EGC, evaluation of LNM preoperative is benefit for determination of therapeutic modalities. Curative surgery has been considered to be the optimal and standard treatment, however, unnecessary lymphadenectomy may lead to complications and decline in the life quality. Now one of the most notable trends is that minimal access surgery dominates the treatment of early stage diseases, minimally invasive surgery and endoscopic resection (ER) such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are available. However, the criteria of ER are not definite in China. The present study would provide some clinical evidence for the application of ER according to the analysis of risk factors of LNM of EGC.

Methods: From January 2002 to July 2012, patients with EGC underwent surgical resection meeting the inclusion criteria were studied retrospectively, the clinicopathological factors of the patients such as gender, age, tumor size, location, macroscopic type, histological differentiation and biological markers were investigated.

Results: The incidence of EGC was 15.4% (742/4,821), when exploratory laparotomy and fistulation were ruled out, the surgical rate of EGC was 17.6% (692/3,935), the ER rate of EGC was only 6.7% (50/742). A total of 627 EGC patients were included in the study, and the rate of LNM was 14.4% (90/627), while the LNM rates of mucosal and submucosal EGC were 6.1% (21/343) and 24.3% (69/284), respectively. Univariate analysis revealed that tumor location, size, macroscopic type, histological differentiation, ulceration, depth of invasion and involvement of lymphatic were associated with LNM of EGC. Tumor size, histological differentiation, depth of invasion and involvement of lymphatic were showed to be independent risk factors related to LNM by multivariate analysis.

Conclusions: Tumor size, histological differentiation, depth of invasion and involvement of lymphatic were independent risk factors related to LNM of EGC. The indication criteria for ER would be extended to less than 3 cm in diameter for differentiated intramucosal cancers without lymphovascular invasion, regardless of the presence of ulceration.

Keywords: Early gastric cancer; lymph node metastasis (LNM); endoscopic resection (ER); surgery