Development of new brain metastases in triple negative breast cancer

Background: Brain metastases are common in patients with breast cancer, and those with triple negative status have an even higher risk. Triple negative status is currently not considered when managing brain metastases. Objective: To determine whether triple negative breast cancer (TNBC) patients with brain metastases have a higher burden of intracranial disease and whether WBRT has a survival benefit in this cohort of patients. Methods: We conducted a retrospective cohort study with 85 patients meeting the inclusion criteria. Results: 25% of patients had TNBC. 95% of the patients in this study received SRS and 48% received WBRT. The average number of new brain metastases from time of initial brain imaging to radiation therapy was 0.67 ± 1.1 in the non-TNBC status patients and 2.6 ± 3.7 in the triple negative status patients (p = 0.001). A cox proportional hazards model showed that WBRT does not significantly affect overall survival in patients with TNBC (HR 1.48; 95% CI 0.47–4.67; p = 0.50). Conclusion: Our findings highlight the highly aggressive intracranial nature of TNBC. The rate of new brain metastasis formation is higher in TNBC patients compared to non-TNBC patients. Furthermore, there is no survival benefit for WBRT in TNBC patients. These findings are relevant for clinicians planning brain radiation for TNBC patients as they may find more brain metastases at the time of brain radiation than they anticipated based on initial brain imaging.