Analysis of Predictive Factors Related to Lymph Node Metastasis in Patients with Undifferentiated Early Gastric Cancers

Abstract

Aim: Studies are now in progress, but limited, to explore the possibility of using endoscopic mucosal resection (EMR) to manage early gastric cancer (EGC) with undifferentiated histological type (poorly differentiated adenocarcinoma and signet-ring cell carcinoma), an expanded indication. If predictive factors for undifferentiated EGC with a negligible risk of LNM can be defined, EMR instead of unnecessary surgery will probably be preferred. Methods: A total of 362 patients with undifferentiated EGC who had undergone a curative resection in our hospital from 2002 to 2006 were analyzed retrospectively. Nine clinicopathological factors (age, sex, location of tumor, macroscopic type, ulcer finding on EGD, histological type, size, depth of invasion of tumor, lymphatic-vascular involvement) were assessed with the chi-square test and then factors found to be significant (p < 0.05) in the univariate analysis were included in a subsequent multivariate logistic regression analysis in order to identify the variables independently which considered to have influence on the LNM. Results: Undifferentiated EGC had a larger proportion of mid-body located and depressed/ulcerative findings. LNM was found in 31 patients (8.5%). Among the 6 factors found to be significantly in the univariate analysis, two independent risk factors, namely, ulcer finding in the tumor defined endoscopically and presence of lymphatic involvement remained independent risk factors for LNM in the multivariate analysis (Table 1). In the further analysis focused on the two positive factors, LNM was observed in 0.9%, 75% of patients who had neither, both factors respectively. Conclusions: Ulcer finding in the tumor was the only independent available predictive risk factor for LNM before surgery or EMR. However, we must be prudent in its interpretation because of interobserver variation and malignant cycle. Therefore, this study suggests that it is premature to extend the indication range of EMR to undifferentiated EGC, particularly in the case of ulcerative lesion. Table 1Multivariate Analysis of Potential Risk Factors for Lymph Node Metastasis in Patients with Undifferentiated EGC Variables ∗ Variable factors consisting of significant factors identified by univariate analysis were adopted. CI = confidence interval, PD = poorly differentiated Odds Ratio (95% CI) P value Age (>55) 1.9 (0.6-6.3) 0.256 Location of tumor Lower third 1.8 (0.1-21.0) 0.618 Ulceration (Positive) 3.3 (1.1-10.6) 0.041 Histological type PD adenocarcinoma 1.4 (0.4-4.9) 0.562 Depth of invasion of tumor Submucosa 0.5 (0.1-2.3) 0.409 Lymphatic-vascular involvement Positive 147.9 (30.6-714.8) <0.001 ∗ Variable factors consisting of significant factors identified by univariate analysis were adopted. CI = confidence interval, PD = poorly differentiated Open table in a new tab