Recursive Partitioning Analysis for the Prediction of Stereotactic Radiosurgery Brain Metastases Lesion Control |
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Authors: | George Rodrigues Jaap Zindler Andrew Warner Frank Lagerwaard |
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Affiliation: | 1. bDepartment of Epidemiology and Biostatistics, University of Western Ontario, London, Ontario, Canada;2. cDepartment of Radiation Oncology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands;3. aDepartment of Radiation Oncology, London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada |
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Abstract: | Purpose.The objective of this investigation was to identify independent pretreatment factors that predict for control of local brain metastases (BM) in a large single-institution series of patients receiving stereotactic radiosurgery (SRS). Recursive partitioning analysis was used to potentially identify a class of patients with durable lesion control characteristics.Methods.A retrospective SRS database containing baseline characteristics, treatment details, and follow-up data of newly diagnosed patients with 1–3 BM (on magnetic resonance imaging) treated with linear accelerator-based SRS was created. Three study endpoints were used: time to progression (primary endpoint, individual lesion progression; n = 536), time to first progression (secondary endpoint, first lesion progression on an individual patient basis; n = 380), and overall survival (secondary endpoint; n = 380). Recursive partitioning analysis (RPA) was performed to identify predictors of time to progression.Results.Multivariable analysis demonstrated that lesion aspect/phenotype and radiotherapy schedule were independent factors associated with both progression outcomes. Presence of tumor necrosis was found to be associated with a significant hazard of progression (hazard ratio >3), whereas use of the most intense radiotherapy fractionation schedule (21 Gy in one fraction) was associated with significant reductions in progression (hazard ratio <0.3). RPA using SRS dose and lesion aspect/phenotype was created and described three distinct prognostic groups.Conclusions.RPA of a large retrospective database of patients receiving SRS confirmed previous observations regarding the importance of SRS dose and lesion aspect/phenotype in lesion control and overall survival. The SRS lesion analysis may help to stratify future clinical trials and better define patient care options and prognosis. |
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Keywords: | Brain metastases Stereotactic radiosurgery Recursive partitioning analysis Predictive modeling Local control |
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