Risk analysis of lymph node metastasis in 285 patients with superficial esophageal squamous cell carcinoma

Abstract

Objective To identify risk factors of lymph node metastasis in superficial esophageal squamous cell carcinoma (ESCC), and to provide evidence for treatment choice under endoscope. Methods From January 2007 to December 2011, 285 patients with pathologically diagnosed ESCC who received surgery and had clear record of lymph nodes resection were enrolled. The clinical pathological data of these patients were analyzed, including age, gender, smoking and drinking history, history of cancer, family history of cancer, location, tumor size, presence of esophageal, depth of infiltration, differentiation, and vascular cancer embolus. Univariate analysis (chi square test or Fisher exact probability method) and multivariate Logistic regression analysis were performed for risk factors of lymph node metastasis assessment.According to the rates of lymph node metastasis, patients were divided into three groups as follows: low risk, high risk and extremely high risk of lymph node metastasis. Kaplan-Meier method was used to calculate the average survival time and cumulative five years survival rate. Results Among the 285 patients with ESCC, 40(14.0%) patients with lymph node metastasis.The results of univariate analysis showed that location (χ2=9.333), tumor length (Fisher exact probability method), depth of infiltration (χ2=9.327), differentiation degree (Fisher exact probability method) vascular cancer embolus (Fisher exact probability method) were significantly associated with lymph node metastasis (all P<0.05). The results of multivariate analysis indicated that tumor length over 5 cm, invasion to submucosal layer and vascular cancer embolus were independent risk factors of lymph node metastasis, and the odd ratio was 17.408(95% confidence interval (CI) 1.557 to 194.686), 3.471(95%CI 1.440 to 8.365) and 6.256(95%CI 1.787 to 21.910), respectively. The lymph node metastasis rates of patients in low risk, high risk and extremely high risk group were 5.2%(6/115), 15.8%(24/152) and 10/18, respectively; the average survival times were (69.9±2.4), (63.8±2.1) and (51.7±1.7) months, respectively. The cumulative five years survival rates were 59%, 51% and 31%, respectively, and the difference was statistically significant (χ2=6.816, P=0.033). Conclusions The risk of lymph node metastasis is high in ESCC patients with tumor length over 5 cm, invasion to submucosal layer and vascular cancer embolus, and the prognosis is poor. Lymph node metastasis should be considered when endoscopic therapy is chosen. Key words: Superficial esophageal squamous cell carcinoma; Lymphatic metastasis; Predictors; Prognosis