Use of Stereotactic Radiosurgery in Elderly and Very Elderly Patients With Brain Metastases to Limit Toxicity Associated With Whole Brain Radiation Therapy

Purpose We evaluated the toxicity associated with stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) in elderly and very elderly patients with brain metastases, as the role of SRS in geriatric patients who would traditionally receive WBRT is unclear. Methods and Materials We conducted a retrospective review of elderly patients (aged 70-79 years) and very elderly patients (aged ≥80 years) with brain metastases who underwent RT from 2010 to 2015 at Johns Hopkins Hospital. Patients received either upfront WBRT or SRS for metastatic solid malignancies, excluding small cell lung cancer. Acute central nervous system toxicity within 3 months of RT was graded using the Radiation Therapy Oncology Group acute radiation central nervous system morbidity scale. The toxicity data between age groups and treatment modalities were analyzed using Fisher's exact test and multivariate logistic regression analysis. Kaplan-Meier curves were used to estimate the median overall survival, and the Cox proportion hazard model was used for multivariate analysis. Results A total of 811 brain metastases received RT in 119 geriatric patients. The median overall survival from the diagnosis of brain metastases was 4.3 months for the patients undergoing WBRT and 14.4 months for the patients undergoing SRS. On multivariate analysis, WBRT was associated with worse overall survival in this cohort of geriatric patients (odds ratio [OR] 3.7, 95% confidence interval [CI] 1.9-7.0, P<.0001) and age ≥80 years was not. WBRT was associated with significantly greater rates of any grade 1 to 4 toxicity (OR 7.5, 95% CI 1.6-33.3, P=.009) and grade 2 to 4 toxicity (OR 2.8, 95% CI 1.0-8.1, P=.047) on multivariate analysis. Elderly and very elderly patients did not have significantly different statistically acute toxicity rates when stratified by age. Conclusion WBRT was associated with increased toxicity compared with SRS in elderly and very elderly patients with brain metastases. SRS, rather than WBRT, should be prospectively evaluated in geriatric patients with the goal of minimizing treatment-related toxicity.