The estimated dose of radiation to immune cells predicts lymphopenia and reveals technique-Dependent immune sparing in postoperative radiotherapy for early esophageal cancer

作者：He Y, Zeng X, Zhou L, Wang X, Sheng S, Wang J · 发表于：Strahlentherapie und Onkologie : Organ der Deutschen Rontgengesellschaft ... [et al] · 年份：2026 · DOI：10.1007/s00066-026-02576-3

BACKGROUND: Radiation-induced lymphopenia (RIL) affects patient survival, but previous studies have mostly focused on locally advanced patients receiving chemoradiotherapy, which involves many confounding factors. This study aimed to investigate whether the estimated dose of radiation to immune cells (EDRIC) correlates with hematologic toxicity (especially lymphopenia) in early-stage esophageal squamous cell carcinoma (ESCC) patients treated with postoperative radiotherapy alone, and to compare EDRIC differences among four modern radiotherapy techniques. MATERIALS AND METHODS: We retrospectively analyzed 30 patients with early-stage ESCC who received postoperative radiotherapy (5040 cGy in 28 fractions) between 2020 and 2025. None of the patients received chemotherapy or immunotherapy, ensuring treatment homogeneity. EDRIC was calculated using the Ladbury formula. Four treatment plans-intensity-modulated radiotherapy (IMRT), volumetric-modulated arc therapy (VMAT), intensity-modulated proton therapy (IMPT), and spot scanning proton arc therapy (SPArc)-were generated for each patient in the RayStation system. EDRIC values were compared using the Friedman test followed by Bonferroni-corrected Wilcoxon signed-rank tests. RESULTS: Complete blood count data were available for 14 of the 30 patients. In this exploratory analysis, only the absolute lymphocyte count (ALC) showed a significant correlation with EDRIC (adjusted R2 = 0.727, 95% CI: 0.35-0.91, P < 0.001). Moreover, after...