Risk factors for lymph node metastases and their prognostic significance in Early Gastric Cancer (EGC) for the Italian Research Group for Gastric Cancer (IRGGC)

Background: Lymph node metastases are present in only about 15% of patients with early gastric cancer (EGC) and for this reason, the majority of these patients do not require lymphadenectomy. In Japan, EGC patients undergo less invasive treatment (endoscopic mucosal resection, wedge resection, laparoscopy). However, the indications for and results of these types of treatment are still uncertain. Methods: In a multicentre retrospective study, we analysed the clinicopathological data referring to 584 early gastric cancer patients who underwent D2 gastrectomy. A comparison was made between patients with and without lymph node metastases in relation to numerous pre- and postoperative variables. Long-term survival and risk factors for lymph node metastases were analysed. The primary aim was to compare our results with those of Western and Japanese authors; we also evaluated the possibility of identifying a subset of patients at low risk of lymph node metastases who may be candidates for endoscopic treatment. Results: The incidence of lymph node metastasis was 14.4%. Univariate and multivariate analyses showed that submucosal infiltration, diffuse histotype, tumour size and Kodama Pen A type were all related to the presence of lymph node metastases. Patients with types I, IIa and IIb mucosal tumours did not present lymph node metastases. Postoperative mortality was 2.2%. Five-year survival in relation to lymph node groups was 95% in N0 patients, 77% in N1 patients and 60% in N2 patients (p = 0.0001, Japanese N-stage). The number of positive lymph nodes also had a prognostic value. Patients with three or fewer positive lymph nodes presented a better 5-year prognosis (83%) than those with more than three positive lymph nodes (48%) (p = 0.0001). Conclusions: Our study confirms that lymph node involvement is an extremely important prognostic factor. For this reason, the therapeutic strategy of our surgical units is as follows: 1) D2 gastrectomy is the standard treatment even in early gastric cancer (EGC); 2) endoscopic mucosal resection (EMR) could be considered first in types I, IIa and IIb tumours that are diagnosed as limited to the mucosal layer.