Clinical and dosimetric predictors of acute severe lymphopenia during radiation therapy and temozolomide for high-grade glioma
Menée sur 183 patients atteints d'un gliome de haut grade traité entre 2007 et 2012 par radiothérapie en combinaison avec le témozolomide, cette étude identifie les facteurs prédictifs, en particulier les paramètres dosimétriques de la radiothérapie, associés à une lymphopénie aiguë sévère
Purpose : Acute severe lymphopenia (ASL) frequently develops during radiation therapy (RT) and 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 (DVH) parameters. ASL was defined as TLC<500/ul within the first 3 months from the start of RT. Stepwise logistic regression analysis (SLRA) was used to determine the most important predictors of ASL.
Results : Fifty-three patients (29%) developed ASL. Patients with ASL had significantly worse OS than those without (median 12.5 versus 20.2 months, respectively, P<0.001). SLRA identified female gender (odd ratio [OR], 5.30; 95% confidence interval [CI], 2.46-11.41), older age (1.05; 1.02-1.09), lower baseline TLC (0.92; 0.87-0.98), and higher brain V25Gy (volume receiving 25Gy) (1.03; 1.003-1.05) as the most significant predictors for ASL. Brain V25Gy<56% appeared as the optimal threshold (OR 2.36; 95% CI 1.11-5.01), with ASL rate of 38% versus 20% above and below this threshold, respectively (P=0.006).
Conclusions : Female gender, older age, lower baseline TLC, and higher brain V25Gy are significant predictors of ASL during RT+TMZ for HGG. Maintaining the V25Gy of brain below 56% may reduce the risk of ASL.
International Journal of Radiation Oncology • Biology • Physics , résumé, 2014