2103 - A Nomogram Predicting Radiation-Related Lymphocyte Recovery and Its Prognostic Value for Survival in Locally Advanced Esophageal Squamous Cell Carcinoma
Presenter(s)
H. Ji1, Y. Su2, M. Liu1, Y. Wang1, Q. An1, Y. Jia1, Z. Zhang1, J. Yan1, J. Bai1, P. Zhang1, and Z. Zhou2; 1Department of Radiation Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China, 2Department of Radiation Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
Purpose/Objective(s): This study aimed to evaluate the prognostic significance of radiation-related lymphocyte recovery in locally advanced ESCC, identify independent factors associated with lymphocyte recovery, and develop a clinically applicable nomogram for predicting lymphocyte recovery.
Materials/Methods: 233 patients with stage II-IVa ESCC who received definitive radiotherapy and developed radiation-induced lymphopenia were retrospectively analyzed and allocated to training (n=163) and validation (n=70) cohorts by random sampling. Patients were stratified into three groups based on lymphocyte recovery status at 1 month (P1) and 3 months (P3) post-radiotherapy: those who didn't recover at P1 nor P3 were divided into Group 0, those who recovered both at P1 and P3 were divided into Group 2, and the others were divided into Group 1. Kaplan-Meier analysis and log-rank test were used to compare overall survival (OS) and progression-free survival (PFS). Multivariate logistic regression was performed to identify predictors of satisfactory lymphocyte recovery and to develop a nomogram, which was internally validated.
Results: With median follow-up of 44 months, median OS was 26.4 months and median PFS was 13.9 months. Median OS for Groups 0, 1, and 2 was 16.0, 26.0, and 50.0 months, respectively (p<0.001); median PFS was 10.2, 12.0, and 36.6 months (p<0.001). Multivariate analysis identified ECOG performance status of 1 (OR 0.41, 95% CI 0.19-0.89, p=0.023) was an independent predictor of unsatisfactory lymphocyte recovery, while planning target volume <210 cm³(OR 2.10, 95% CI 1.00-4.41, p=0.051), and thoracic spine V5 <57.3% (OR 5.55, 95% CI 2.71-11.36, p<0.001) were associated with satisfactory lymphocyte recovery. The nomogram, incorporating ECOG performance status, planning target volume, and thoracic spine V5, achieved AUCs of 0.77(95% CI 0.69-0.84) and 0.75(95% CI 0.64-0.87) in the training and validation cohorts, respectively.
Conclusion: In our study, superior lymphocyte recovery after definitive radiotherapy is independently associated with improved OS and PFS in locally advanced ESCC. ECOG performance status, planning target volume, and thoracic spine V5 predict lymphocyte recovery. The proposed nomogram demonstrates reliable discrimination and may facilitate lymphocyte-sparing radiotherapy planning.