Construction of a prognostic hierarchical model for patients with HER2 positive breast cancer with brain metastases.

Abstract

e13030 Background: Brain metastasis occurs in about 50% of advanced HER2-positive breast cancer patients. In clinical practice, we need accurate model to predict the patients’ survival time. According to survival time, we can arrange reasonable treatment strategy for HER2 positive breast cancer with brain metastases. Methods: The study recruited HER2-positive breast cancer brain metastasis (BCBM) patients who attended the Fifth Medical Center of PLA General Hospital from June 2003 to June 2022.All statistics were performed using SPSS version 22.0 and R version 3.4.3 software. Results: This study included 300 patients with HER2-positive BCBM. The median age at Brain Metastases diagnosis was 48.5 years, and the median Brain Metastases Overall Survival time (BMOS) was 18.0 months (95% CI: 14.6-21.4). A single-factor analysis of BMOS revealed that age, number of brain metastasis lesions, number of extracranial lesions during BCBM, radiotherapy after BCBM, anti-HER2 therapy after BCBM, and survival prognosis after BCBM were associated with survival prognosis after diagnosis of BCBM. According to a multi-factor analysis, the age, the number of brain metastases, radiotherapy after BCBM, and anti-HER2 therapy after BCBM were all independent factors influencing survival after diagnosis of BCBM. Different independent prognostic factors comprised the patient hierarchical evaluation model. Patients' warning scores range from 0 to 7. We divided the patients into three groups with obvious differences in prognosis： Low- intermediate-risk (score≥1), stroke group (score≥3) and high-risk group (score≥6). The patient prognosis was worse when the warning score was high. The results of Kaplan-Meier survival curve analysis showed significant prognosis differences between the three groups of patients (P < 0.0001). The mean Area Under Curve of the receiver operating characteristic curve for 1-yeasr, 2-year, and 3-year prognosis prediction was 0.69,0.71, and 0.67, respectively. For low-risk patients, the prognosis was significantly improved by using any anti-HER2 medications (P<0.05). Trastuzumab + Pertuzumab can significantly improve the prognosis of patients at intermediate risk (P<0.001, HR=0.24,95%CI: 0.13-0.43). Patients in the intermediate-risk group received both anti-HER2 medication and combined radiotherapy significantly prolonged BMOS in patients who received only drug therapy or radiotherapy (P=0.0132). Conclusions: A survival and prognostic stratification model was constructed based on the clinicopathological characteristics and treatment pattern of a large cohort of HER2-positive breast cancer patients with brain metastases, and the patients were divided into the low-risk group, intermediate-risk group and high-risk group. The optimal individualized treatment strategy was recommended according to different groups.