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

• Published in: International journal of radiation oncology, biology, physics Vol. 92; no. 5; pp. 1000 - 1007
• Main Authors: Huang, Jiayi, DeWees, Todd A., Badiyan, Shahed N., Speirs, Christina K., Mullen, Daniel F., Fergus, Sandra, Tran, David D., Linette, Gerry, Campian, Jian L., Chicoine, Michael R., Kim, Albert H., Dunn, Gavin, Simpson, Joseph R., Robinson, Clifford G.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2015
• Subjects: Acute Disease; Adult; Age Factors; Aged; Aged, 80 and over; Antineoplastic Agents, Alkylating - adverse effects; BRAIN; Brain - radiation effects; Brain Neoplasms - drug therapy; Brain Neoplasms - mortality; Brain Neoplasms - pathology; Brain Neoplasms - radiotherapy; Chemotherapy, Adjuvant; Cranial Irradiation - adverse effects; Cranial Irradiation - methods; Dacarbazine - adverse effects; Dacarbazine - analogs & derivatives; Female; Glioma - drug therapy; Glioma - mortality; Glioma - pathology; Glioma - radiotherapy; GLIOMAS; Hematology, Oncology and Palliative Medicine; Humans; Lymphocyte Count; LYMPHOCYTES; LYMPHOPENIA; Lymphopenia - etiology; Lymphopenia - mortality; Male; Middle Aged; Odds Ratio; PATIENTS; RADIATION DOSES; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Radiotherapy Dosage; REGRESSION ANALYSIS; Sex Factors; Young Adult
• ISSN: 0360-3016; 1879-355X; 1879-355X
• DOI: 10.1016/j.ijrobp.2015.04.005

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. 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. 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). 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.