Clinical and Dosimetric Predictors of Acute Severe Lymphopenia during Radiation Therapy and Concurrent Temozolomide for High-Grade Glioma

Jiayi Huang, Todd A. Dewees, Shahed N. Badiyan, Christina K. Speirs, Daniel F. Mullen, Sandra Fergus, David D. Tran, Gerry Linette, Jian L. Campian, Michael R. Chicoine, Albert H. Kim, Gavin Dunn, Joseph R. Simpson, Clifford G. Robinson

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59 Scopus citations

Abstract

Purpose Acute severe lymphopenia (ASL) frequently develops during radiation therapy (RT) and concurrent temozolomide (TMZ) for high-grade glioma (HGG) and is associated with decreased survival. The current study was designed to identify potential predictors of ASL, with a focus on actionable RT-specific dosimetric parameters. Methods and Materials From January 2007 to December 2012, 183 patients with HGG were treated with RT+TMZ and had available data including total lymphocyte count (TLC) and radiation dose-volume histogram parameters. ASL was defined as TLC of <500/μL within the first 3 months from the start of RT. Stepwise logistic regression analysis was used to determine the most important predictors of ASL. Results Fifty-three patients (29%) developed ASL. Patients with ASL had significantly worse overall survival than those without (median: 12.5 vs 20.2 months, respectively, P<.001). Stepwise logistic regression analysis identified female sex (odds ratio [OR]: 5.30; 95% confidence interval [CI]: 2.46-11.41), older age (OR: 1.05; 95% CI: 1.02-1.09), lower baseline TLC (OR: 0.92; 95% CI: 0.87-0.98), and higher brain volume receiving 25 Gy (V25Gy) (OR: 1.03; 95% CI: 1.003-1.05) as the most significant predictors for ASL. Brain V25Gy <56% appeared to be the optimal threshold (OR: 2.36; 95% CI: 1.11-5.01), with an ASL rate of 38% versus 20% above and below this threshold, respectively (P=.006). Conclusions Female sex, older age, lower baseline TLC, and higher brain V25Gy are significant predictors of ASL during RT+TMZ therapy for HGG. Maintaining the V25Gy of brain below 56% may reduce the risk of ASL.

Original languageEnglish
Pages (from-to)1000-1007
Number of pages8
JournalInternational Journal of Radiation Oncology Biology Physics
Volume92
Issue number5
DOIs
StatePublished - Aug 1 2015

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