Brain metastasis in de novo breast cancer: An updated population-level study from SEER database

Although there are current studies on breast cancer brain metastasis, population-level analysis is still lacking. As treatment for metastatic breast cancer has improved, an updated population-level analysis is necessary. Our aim was to use the SEER database to characterize the incidence and survival of patients with brain metastases at the initial diagnosis of breast cancer.

Patients with breast cancer from 2010 to 2018 were identified using the SEER database. The stratified incidence and median survival of patients with BM at diagnosis were described. Multivariate logistic and Cox regression were performed to determine the covariates associated with brain metastasis and survival outcomes, respectively. Multiple comparisons based on Cox proportional hazards model were performed for the analysis of interactive effects on overall survival.

A total of 2,248 patients with brain metastases at the initial diagnosis of breast cancer were identified, accounting for 0.40% of all patients with breast cancer, and 7.26% of patients with metastatic disease. Incidence proportions were highest, and survival outcomes were worst among patients with hormone receptor (HR)-negative human epidermal growth factor receptor 2 (HER2)-positive and triple-negative subtypes. For patients with brain metastases, the prognostic differences among different molecular subtypes have been gradually narrowing, and the survival benefits from various treatment methods have been all increased over time.

Our study provides an updated population-level estimate of the incidence and survival for patients with brain metastases at the diagnosis of breast cancer, thus may help early identification, prognostic stratification and treatment planning for such patients.