Disparities in Use of Salvage Whole Brain Radiation Therapy vs. Salvage Stereotactic Radiosurgery After Initial Stereotactic Radiosurgery for Brain Metastases.

PURPOSE/OBJECTIVE(S) Patients undergoing stereotactic radiosurgery (SRS) for brain metastases often relapse and require additional radiation. Due to the paucity of data, the decision to offer salvage re-irradiation with whole brain radiation therapy (WBRT) versus SRS is made on an individual basis. Our objective is to determine the clinical and demographic factors associated with SRS versus WBRT for salvage of first intracranial failure (ICF), i.e., local and/or locoregional failures. MATERIALS/METHODS We identified a cohort of 374 consecutive patients with brain metastases treated with SRS in the definitive or postoperative setting, at a single institution, from August 2014 to September 2019. Eligible patients received subsequent salvage radiation at our institution with WBRT or SRS at least one month after initial SRS. Clinical and demographic characteristics were retrospectively recorded. Univariate (UVA) and multivariate analyses (MVA) were performed to determine if there was a significant correlation between these factors and the use of salvage SRS versus WBRT. Odds ratios (ORs) and corresponding P-values were estimated from logistic regression model. A survival analysis was also performed to assess the impact of these factors on survival. All tests were two sided and P-value of 70, Stable/absent systemic disease, and receipt of salvage SRS. CONCLUSION The strongest factor associated with selection of salvage WBRT vs. SRS for ICF following initial SRS is local progression. There was also found to be a significant disparity in the form of decreased salvage SRS for male patients that remained significant when controlling for other disease and socioeconomic factors. Possible etiologies of this difference could be provider or patient driven but warrant further exploration. In this cohort, salvage SRS was associated with a statistically significant improvement in OS, however, this may also represent a selection bias. AUTHOR DISCLOSURE Y.S. Soni: None. B.J. Rich: None. D. Kwon: None. W. Zhao: None. D.L. John: None. C.S. Seldon: None. C. Benjamin: None. R. Benveniste: None. R.J. Komotar: None. P. Prieto: None. M. De La Fuente: None. G. Azzam: None. E.A. Mellon: None. T. Diwanji: None.