METASNCore: A new tool for palliative whole brain radiotherapy (WBRT) assessment in the era of targeted therapies.

Abstract

e24154 Background: Palliative WBRT has been the main treatment for multiple brain metastases (BM). Recent studies report no benefit in survival or quality of life of WBRT compared to palliative supportive care in patients (pts) with poor prognosis. Several scores have been developed to support decision-making for selection of patients; despite this, the scales implemented so far do not consider the substantial impact of new developments in recent years. The purpose of this study was to develop and statistically validate a prognostic score in palliative pts with BMs who underwent WBRT. Methods: 239 pts with BM who received palliative WBRT between 2013-2022 in our center were analyzed retrospectively. Relevant clinicopathological features and their association with overall survival (OS) were measured using univariate and multivariate Cox regression models. The score was designed according to the value of the β coefficient of each variable with statistical significance (p < 0.05) in the multivariate model. Extra 0.5 points were added to all variables with a statistical significance of p < 0.001. Once the score was established, a comparison was performed according to Kaplan-Meier and the survival curves were analyzed with the log-rank test. Results: 149 pts (62.3%) were male and median age was 60 years. 139 (58,2%) were lung cancer (22,8% small cells), 35 (14,6%) breast cancer (53% luminal). 124 pts had ECOG 0-1 (52,1%) and 114 (47,9%) ECOG 2-3, 169 (70,7%) had extracranial disease and the most common symptom was headache (24,3%). All patients received 30Gys in 10 sessions. 37 pts (15,5%) had a specific target mutation and 15 (6,3%) received targeted therapy after WBRT. Median OS was 3,74 months (95% CI 3,28-4,20). After the multivariate analysis: ECOG, gastrointestinal (GI) or urothelial cancer, previous RT, protein C reactive (PCR), target drug treatment and chemotherapy after WBRT were shown to have independent prognostic value for the OS. Our score found 16% to 33% higher risk of the event taking place before per each point in the score. (HR (CI 95%): 1.243 (1.164 - 1.329). p < 0.001) (table 1). We found that 48 pts were in group 0-4 points with mOS 6,89ms (CI 95% 3,18-10,62), 80 in group 4-7 points with mOS 4,01ms (CI 95% 3,40-4,62) and 90 pts in group > 7 points with mOS 2,72ms (CI 95% 1,93-3,52). Conclusions: Some items in our cohort like ECOG, primary tumor site, PCR or post-WBRT systemic treatment (specially target treatment) are associated with OS and they could be useful in a score to select palliative pts to receive WBRT. More prospective and multicenter studies are necessary to corroborate our findings.[Table: see text]