Whole brain radiation therapy for patients with brain metastases: survival outcomes and prognostic factors in a contemporary institutional series

Abstract

Purpose: To study survival outcomes and prognostic factors in patients undergoing whole brain radiation therapy (WBRT) for brain metastases in the contemporary setting.

Methods: Patients undergoing WBRT from 2013-2021 were retrospectively included in an ethics-approved institutional database. Patient and treatment characteristics were assessed, including patient age, primary tumor histology, Karnofsky Performance Status (KPS), extracranial disease, as well as WBRT dose. Overall survival (OS) was calculated from onset of WBRT using the Kaplan-Meier method.

Results: A total of 328 patients (median age 63 years) were included. Most patients (52%) had ≥ 10 brain metastases, and 17% had leptomeningeal disease. WBRT was delivered with 10 × 3 Gy (64%), 5 × 4 Gy (25%), or other regimens (11%). Median follow-up was 4.4 months (range, 0.1-154.3), and median OS was 4.7 months (95%CI, 3.8-6.0). OS differed between histologies (p = 0.01), with the longest survival seen in breast cancer (median 7.7 months). Patients with KPS of 90-100 survived for a median of 8.3 months, compared to 4.1 months with KPS 70-80, and 1.7 months with KPS < 70 (p < 0.01). Multivariate analyses revealed that KPS had the largest impact on survival. Patients who received a WBRT dose of ≥ 30 Gy also had a reduced risk of death (HR 0.45; p < 0.001). Survival differed between subgroups reclassified according to the Rades scoring system (p < 0.01).

Conclusion: Survival outcomes of patients undergoing WBRT in the contemporary era appear comparable to historical cohorts, although individual patient factors need to be considered. Patients with otherwise favorable prognostic factors may benefit from longer-course WBRT.

Keywords: Brain metastases; WBRT; Whole brain radiation therapy; Whole brain radiotherapy.

Fig. 1

Kaplan-Meier estimates of overall survival following WBRT for brain metastases, stratified by primary tumor type (left panel) and KPS (right panel). More favorable survival outcomes were observed in patients with breast cancer, as well as in those with a good performance status. Abbreviations: KPS Karnofsky Performance Status, NSCLC non-small cell lung cancer, SCLC small cell lung cancer, WBRT whole brain radiation therapy

Fig. 2

Multivariate Cox regression analysis showing the HR of death after WBRT in patients with brain metastases. Abbreviations: HR hazard ratio, KPS Karnofsky Performance Status, NSCLC non-small cell lung cancer, SCLC small cell lung cancer, WBRT whole brain radiation therapy

Fig. 3

OS in patients classified according to the Rades scoring system, which was previously developed for patients undergoing WBRT for brain metastases. Survival outcomes differed between Rades subgroups in this more contemporary cohort, with a stepwise increase in OS seen from group A (poorest outcome) to D (best outcome). Abbreviations: OS overall survival, WBRT whole brain radiation therapy