464P - Developing a prognostic risk stratification model and treatment options for HER2-positive breast cancer brain metastasis

Background

Brain metastasis occurs in about 50% of advanced HER2-positive BC patients. Moreover, there are still a lot of unresolved clinical issues, such as how to classify patients and adapt targeted therapy to better prolong survival.

Methods

The study recruited HER2-positive BCBM patients who attended the Fifth Medical Center of PLA General Hospital from 2003 to 2022. 32 HER2-positive BCBM patients treated between 2008 and 2022 at the First Hospital of Peking University and 43 HER2-positive BCBM patients from 2012 to 2022 at Xi'an Jiaotong University First Affiliated Hospital were included as an independent test set. All statistical methods and survival analyses were performed in SPSS 22.0 and R version 4.2.1.

Results

This study included 300 patients with HER2-positive BCBM. According to 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-risk (score≥1), median-risk group (score≥3), and high-risk group (score≥6). The patient prognosis was worse when the warning score was high. The results of the survival analysis showed significant differences between the three groups of patients (P<0.0001). The mean AUC values for 1-year, 2-year prognosis prediction was 0.69, 0.71, respectively. We acquired clinical data from 75 patients from other centers to further assess our model's generalization capabilities. Patients are categorized using the prognostic grading evaluation model, and prognostic analysis is performed (P<0.0001). The AUC values for 1-year, 2-year prognostic forecasts were 0.94. Patients in the median-risk group who received drug therapy combined with radiotherapy had significantly prolonged BMOS compared with the patients who received only drug therapy or radiotherapy (P=0.01).

Conclusions

A survival and prognostic stratification model was constructed based on the clinicopathological characteristics of a large cohort of HER2-positive BCBM patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.