Favorable prognosis of breast cancer brain metastases patients with limited intracranial and extracranial metastatic lesions

Background Breast cancer brain metastases (BCBM) are highly heterogenous with widely differing survival. The prognosis of the oligometastatic breast cancer (BC) patients with brain metastases (BM) has not been well studied. We aimed to investigate the prognosis of BCBM patients with limited intracranial and extracranial metastatic lesions. Methods Four hundred and forty-five BCBM patients treated between 1st January 2008 and 31st December 2018 at our institute were included. Clinical characteristics and treatment information were obtained from patient’s medical records. The updated breast Graded Prognostic Assessment (Breast GPA) was calculated. Results The median OS after diagnosis of BM were 15.9 months. Median OS for patients with GPA 0–1.0, 1.5–2, 2.5–3 and 3.5–4 were 6.9, 14.2, 21.8, 42.6 months respectively. The total number of intracranial and extracranial metastatic lesions, in addition to the Breast GPA, salvage local therapy and systemic therapy (anti-HER2 therapy, chemotherapy and endocrine therapy) were demonstrated to be associated with prognosis. One hundred and thirteen patients (25.4%) had 1–5 total metastatic lesions at BM diagnosis. Patients with 1–5 total metastatic lesions had a significantly longer median OS of 24.3 months compared to those with greater than 5 total metastatic lesions with a median OS of 12.2 months ( P < 0.001; multivariate HR 0.55, 95% CI, 0.43–0.72). Among the patients with 1–5 metastatic lesions, median OS for GPA 0–1.0 was 9.8 months, compared to 22.8, 28.8 and 71.0 for GPA 1.5–2.0, 2.5–3.0 and 3.5–4.0 respectively, which is much longer than the corresponding patients with greater than 5 total metastatic lesions, with medium OS of 6.8, 11.6, 18.6 and 42.6 months respectively for GPA 0–1.0, 1.5–2.0, 2.5–3.0 and 3.5–4.0. Conclusions The patients with 1–5 total metastatic lesions demonstrated better OS. The prognostic value of the Breast GPA and the survival benefit of salvage local therapy and continuation of systemic therapy after BM were confirmed.