Incidence of radiation-induced leukoencephalopathy after whole brain radiotherapy in patients with brain metastases

Introduction: Whole brain radiation therapy (WBRT) remains a recommended treatment for patients with brain metastases in terms of symptom palliation, especially when extracranial systemic disease is present. The aim of the study was to determine the clinical correlation between pre-existing leukoaraiosis and posterior leukoencephalopathy secondary to WBRT. Methods and materials: We retrospectively reviewed the results of WBRT treatment in 44 patients with melanoma brain metastases. The neuroimaging abnormalities of the white matter (T2-weighted MRI) were graded over time. Results: From the 37 evaluable patients the mean age was 53 years old, 23 male and 14 female. Vascular risk factors were present in 22 patients (59.5%). The WBRT total dose was 20 Gy/5fr (n=21) and 3 0 Gy/10fr (n=16). Leukoaraiosis pre-WBRT was observed in 9/37 patients (24.3%) and leukoencephalopathy post-WBRT in 2/37 (5.4%). Univariate analysis of prognostic factors (sex, age and vascular risk factors) for leukoaraiosis was conducted observing statistically significant differences for patients with age >= 65 years old (p=0.003). Nineteen patients survived more than 3 months. Twelve patients (63.2%) suffered from vascular risk factors. Univariate analysis demonstrated previous leukoaraiosis as a prognostic factor for developing further leukoencephalopathy after WBRT (p=0.015). Conclusions: Radiation-induced leukoencephalopathy is greater in patients with pre-existing leukoaraiosis. Because of the potential of long-term survival in a small subset of patients with brain metastases and the risk of radiation-induced dementia, neurotoxicity reduction in patients with leukoaraiosis is an important goal of treatment.