A Reliable Nomogram is Identified to Predict the Overall Survival for Patients with Esophageal Squamous Cancer after Chemoradiation Therapy followed by Surgery

Abstract

Currently there is no reliable nomogram to predict the overall survival (OS) for patients with esophageal squamous cancer (ESCC) after chemoradiation therapy followed by surgery. The purpose of this study is to develop the above nomogram through the correlation of pretreatment clinical features that are commonly indicated for prognosis. We searched through Surveillance, Epidemiology, and End Results (SEER) database. A criterion for the search is listed as follows: (1) patients diagnosed with pathologically proved ESCC; (2) patients diagnosed in 2010-2014(AJCC 2010 7th version); (3) patients with T1-4N0-3M0 disease; (4) patients underwent chemoradiation therapy followed by surgery. Age, ethnicity, sex, Primary Site of the tumor, T stage, N stage were recorded as clinical predictors. These predictors were used in multivariable logistic regression analysis based nomograms to estimate the probabilities of OS. The predictive accuracy and discriminative ability of the nomogram were determined by concordance index (C-index) and calibration curve. Analyses were performed with open-source statistical software R (version 3.2.1). There were 5,508 patients with ESCC diagnosed in 2010-2014, 326 patients were identified. A total of 41% of patients were male. A total of 62% were aged 50 to 70.72% and were in the white race. Proportion of the patients diagnosed in T1, T2, T3, and T4 were 15%, 18%, 63%, and 4%; 92% of the patients were in N0-1 stage; 88.3% of the tumor were located in middle and lower third of esophagus; only 4% had overlapping lesion of esophagus. The 3-year and 4-year OS for the entire cohort of the patients were 53%, 47% with the median survival time of 45 months. Median survival of male and female patients were 38 months vs. 54 months (p=0.024); 3 year survival of patients with white race and other race were 56% vs. 45%, p=0.050; 3 year OS for patients with T1-2 and T3-4 stage were 60.8% vs. 52.4%, p = 0.198. For patients with N0, N1, N2, and N3 stage, 3-year OS were 87.3%, 54.3%, 37.1%, and 0%, p < 0.001. Primary site of the tumor was not the prognostic factors. Nomograms were developed for the predicted OS with age, sex, ethnicity, T stage, and N stage. The calibration curve for probabilities showed relatively good agreement between prediction by nomogram and actual observation. The C-index of the nomograms for predicting for predicting OS is 0.63. The risk of having one of the indications of adjuvant radiation therapy increased with increases in predictors except for clinical T stage. Using clinical information, we produced nomograms, which may relatively accurately predict the probabilities of overall survival for patients with esophageal squamous cancer after chemoradiation therapy followed by surgery. This nomogram may help individualize initial treatment options.