Predicting Post-Radiotherapy Lymphocyte Recovery for Individualized Risk Stratification in Locally Advanced...

The prognostic value of post-radiotherapy (RT) lymphocyte recovery remains unclear in locally advanced esophageal squamous cell carcinoma (ESCC), and tools to predict recovery are lacking. This study evaluated lymphocyte recovery as a survival predictor and developed a prediction model. We analyzed 233 patients (2019-2024; training:validation = 7:3). Lymphocyte recovery was assessed at 1 and 3 months post-RT (ΔALC₁ > 0.41 and ΔALC₃ > 0.25 × 10⁹/L, calculated as ALC at each time point minus ALC at the end of RT). Patients were stratified into three groups by recovery status: no recovery (Group 0), recovery at both time points (Group 2), or at only one time point (Group 1). Multivariate logistic regression identified predictors of lymphocyte recovery, and a nomogram was developed and internally validated. Median overall survival (OS) was 26.4 months and median progression-free survival (PFS) was 13.9 months. OS differed significantly among groups: 16.0 months (Group 0), 26.0 months (Group 1), and 50.0 months (Group 2) (p < 0.001). Median PFS was 10.2, 12.0, and 36.6 months, respectively (p < 0.001). Independent predictors included ECOG 0 and thoracic spine V₅ < 57.3%; planning target volume < 210 cm³ showed a trend toward association (p = 0.051). The nomogram demonstrated AUCs of 0.77 and 0.75 in the training and validation cohorts. Superior lymphocyte recovery appears to be associated with improved survival. The model, if externally validated, may facilitate individualized risk stratification.