Positive lymph node ratio is an important index to predict long-term survival for advanced esophageal squamous carcinoma patients (II∼III) with R0 resection--a SEER-based analysis

Abstract

BackgroundEsophageal squamous carcinoma (ESCC) is one of the most malignant cancers in the world due to nodal metastasis. Therefore, a reasonable nodal staging system is extremely important for further treatment strategies. Recently the positive lymph node ratio (PLNR) is an important prognostic factor in various solid tumors MethodIn this study, we investigated the clinical significance of the PLNR in stage II∼III ESCC patients. We collected the pathological characteristics of 272 stage II∼III ESCC patients from the SEER database from 2004–2016. ROC curves were used to calculate the best cutoff value of the PLNR; Pearson's Chi-square (χ2) and Fisher's exact probability tests were used to compare the clinical baseline and characteristics of patients. For continuous variables, Student's t-test and ANOVA were performed to evaluate statistical significance. Clinical outcomes were estimated by using the Kaplan‒Meier method and log-rank test. Furthermore, univariate and multivariate Cox regression models were utilized to analyze independent prognostic factors of ESCC patients. ResultsConsequently, advanced ESCC patients were effectively stratified into two groups by prognosis using a PLNR cutoff value of 0.15 (P value = 0.04). The median survival time of patients with PLNR <0.15 (n = 145) was much higher than that of patients (n = 127) in the PLNR ≥0.15 group (20.0 vs. 13.0 months, P value < 0.0001). Notably, the PLNR significantly predicted the prognosis of ESCC patients with stage N1 (P value 0.01) and stage III (P value < 0.001) disease. The multivariate Cox proportional hazard model showed that T stage (HR 1.33, 95 % CI 0.97–1.82), tumor size >45 mm (HR 1.32, 95 % CI 1.02–1.70), N stage (HR 1.41, 95 % CI 0.98–2.01) and PLNR ≥0.15 (HR 1.35, 95 % CI 0.87–1.74) were independent risk factors for prognostic prediction in ESCC patients. Meanwhile, 117 II∼III ESCC patients from Shaanxi Provincial People's Hospital shown that the overall survival with a PLNR <0.15 (n = 96) was significantly longer than that with a PLNR ≥0.15 (n = 21) . ConclusionsThe PLNR is useful for accurately predicting clinical outcomes and determining postoperative strategies.