Risk factors and prognostic factors of brain metastasis of triple-negative breast cancer: A single-center retrospective study.

Objective: This retrospective study is to explore the risk factors and prognostic factors of brain metastases of triple-negative breast cancer (TNBC) in a single center.

Methods: Clinical data of patients with stages I-III TNBC were collected. The Kaplan-Meier method, log-rank test, and stepwise COX regression were performed.

Results: The 437 patients with stages I-III TNBC were followed up for five years. Among them, 89 cases (20.4%) developed brain metastases, and they were followed up for 2 years after brain metastasis. The cumulative brain metastasis rates of TNBC patients at six months, one year, two years, three years, and five years were 1.38%, 5.75%, 12.94%, 17.63%, and 21.26%, respectively. Multivariate analysis suggested that the first diagnosis age ≤35 years old, advanced pathological stage, lymph node metastasis, and Ki-67 ≥30% represented the risk factors for brain metastasis. In contrast, the surgical method was a protective factor for brain metastasis. The median survival time after brain metastasis was 4.87 months. The survival rates at one, three, six, 12, and 24 months were 84.27%, 60.67%, 34.83%, 15.69%, and 6.64%, respectively. The age >60 years at first diagnosis, Ki-67 ≥30%, local recurrence, and distant metastasis were closely related to the poor prognosis of TNBC patients with brain metastases, while radiotherapy alone, systemic therapy, and combined chemotherapy and radiotherapy represented the prognostic protective factors.

Conclusions: Patient age, Ki-67 level, metastasis, and treatment methods are the risk factors and prognostic factors for brain metastasis of TNBC. Surgical resection of the primary lesion during the first treatment is essential to reduce the incidence of brain metastases. Close postoperative follow-up (such as brain magnetic resonance imaging [MRI]) within 2-3 years after surgery is recommended to improve the prognosis.