Spleen Dose Influences Overall Survival in the Neo-Adjuvant Treatment of Esophageal Cancer

Several studies demonstrated a significant association between grade IV lymphopenia and the pathologic complete response rate or overall survival (OS) after chemoradiotherapy (CRT) for esophageal cancer (EC). As the spleen is an important pool of lymphocytes, we hypothesized that the dose distribution of the spleen is predictive for overall survival. Therefore, the aim of the current study was to evaluate the impact of the spleen dose on overall survival after neo-adjuvant CRT. All EC patients who were treated with neo-adjuvant CRT (CROSS regimen) in our center between October 2014 and August 2018 were included in this cohort study. All patients were included in our prospective data registration program, in which patient and tumor baseline characteristics as well treatment outcomes are prospectively assessed. After a pre-selection in univariable analysis (p<0.2), a multivariable Cox regression analyses was performed to identify independent predictors for OS. Of the 224 patients who were treated with neo-adjuvant CRT to a total dose of 41.4Gy, surgical resection was performed in 194 cases (86.6%). Univariable and additional multivariable analysis for OS (Table 1) revealed that age (HR: 1.03 (1.00-1.05)); T-stage (HR: 1.85 (1.12-3.07)); body mass index (1,01 (1.01-1.02)) and mean spleen dose (MSD) (HR: 1.04 (1.01.-1.06)) were independent prognostic factors for OS. MSD is an independent prognostic factor for OS and should be recognized as an organ at risk in radiotherapy treatment planning.Abstract 3434; TableCox regression analysis for Overall SurvivalCOX regression for Overall survivalUnivariableMultivariableHRp-valueHR95%CIp-valueAge1.0280.0301.0281.002 - 1.0530.031Gender0.6020.063Cardiac history1.5330.069Body mass index1.0120.0001.0121.006 - 1.0190.000Smoking ever1.211nsReynolds Risk Score >20%1.4060.097AC vs SCC0.3970.019cT1-2 vs cT3-42.0070.0051.8511.116 - 3.0700.017cN0 vs cN+1.4630.121Tumor length1.049nsMean Lung Dose1.011nsMean Heart Dose1.024nsMean Spleen Dose1.0400.0031.0371.010 - 1.0640.007Abbreviations: AC, adenocarcinoma; SCC, squamous cell carcinoma; ns, non-significant. Open table in a new tab