32 A population-based study of melanoma brain metastasis treatment: Has new progress in systemic therapy and new technology in radiotherapy improved patient outcomes?

Abstract

Background: Outcomes for patients with melanoma brain metastases (MBM) have been poor. New radiotherapy technologies and systemic agents have improved outcomes. Outcomes have rarely been studied at the population-level. We undertook a population-based study investigating changes in management and outcome for patients with MBM in Ontario from 2007-2016. Methods: This was a retrospective population-based cohort study of patients treated for MBM in Ontario from 2007-2016. Melanoma was identified through the Ontario Cancer Registry. Treatments and outcome were described by era (2007-2009, 2010-2012, 2013-2016). Treatment with cranial radiotherapy and drugs were defined using Cancer Care Ontario data and supplemented by physician billing and drug reimbursement data. Neurosurgery was identified using CIHI hospital records. Time to event was investigated using Kaplan-Meier curves. Results: From January 2007-June 2016, 1096 patients with MBM were treated. Whole brain radiation therapy was the first brain-directed treatment in 75.5% of patients in 2007-2009, dropping to 52.0% for 2013-2016. Patients receiving stereotactic radiation or other conformal techniques as the first brain treatment increased from 3.4% in 2007-2009 to 21.3% 2013-2016. Use of BRAF/MEK inhibitors and immunotherapy increased: <2.0% in 2007-2009 to 40.9% 2013-2016. One-year and two-year overall survival (OS) following first brain-directed treatment was greater in 2013-2016: 21.8% at one year and 13.8% after two years (Wilcoxon p=0.001). This compared to 12.3% and 6.4% 2007-2009, and 10.7% and 5.5% 2010-2012. Conclusion: The advent of new radiation technologies and systemic treatments for MBM was associated with increased survival and greater avoidance of whole brain radiotherapy.