Prediction of Severe Lymphopenia During Chemoradiation Therapy for Esophageal Cancer: Development and Validation of a Pretreatment Nomogram

Peter S.N. van Rossum, Wei Deng, David M. Routman, Amy Y. Liu, Cai Xu, Yutaka Shiraishi, Max Peters, Kenneth W. Merrell, Christopher Hallemeier, Radhe Mohan, Steven H. Lin

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Abstract

Introduction: In patients with esophageal cancer, occurrence of severe radiation-induced lymphopenia during chemoradiation therapy has been associated with worse progression-free and overall survival. The aim of this study was to develop and validate a pretreatment clinical nomogram for the prediction of grade 4 lymphopenia. Methods and Materials: A development set of consecutive patients who underwent chemoradiation therapy for esophageal cancer and an independent validation set of patients from another institution were identified. Grade 4 lymphopenia was defined as an absolute lymphocyte count nadir during chemoradiation therapy of <0.2 × 103/μL. Multivariable logistic regression analysis was used to create a prediction model for grade 4 lymphopenia in the development set, which was internally validated using bootstrapping and externally validated by applying the model to the validation set. The model was presented as a nomogram yielding 4 risk groups. Results: Among 860 included patients, 322 (37%) experienced grade 4 lymphopenia. Higher age, larger planning target volume in interaction with lower body mass index, photon- rather than proton-based therapy, and lower baseline absolute lymphocyte count were predictive in the final model (corrected c-statistic, 0.76). External validation in 144 patients, among whom 58 (40%) had grade 4 lymphopenia, yielded a c-statistic of 0.71. Four nomogram-based risk groups yielded predicted risk rates of 10%, 24%, 43%, and 70%, respectively. Conclusions: A pretreatment clinical nomogram was developed and validated for the prediction of grade 4 radiation-induced lymphopenia during chemoradiation therapy for esophageal cancer. The nomogram can risk stratify individual patients suitable for lymphopenia-mitigating strategies or potential future therapeutic approaches to ultimately improve survival.

Original languageEnglish (US)
JournalPractical Radiation Oncology
DOIs
StateAccepted/In press - Jan 1 2019

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ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

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van Rossum, P. S. N., Deng, W., Routman, D. M., Liu, A. Y., Xu, C., Shiraishi, Y., Peters, M., Merrell, K. W., Hallemeier, C., Mohan, R., & Lin, S. H. (Accepted/In press). Prediction of Severe Lymphopenia During Chemoradiation Therapy for Esophageal Cancer: Development and Validation of a Pretreatment Nomogram. Practical Radiation Oncology. https://doi.org/10.1016/j.prro.2019.07.010