Background With the progress of medical technology, the survival time of advanced HER2-positive breast cancer patients is significantly prolonged, however, up to 50% of patients will eventually develop brain metastasis. Although radiotherapy is the mainstay treatment for brain metastasis, the dose and frequency of radiotherapy are limited, while drug therapy has become the focus of research in recent years.
Objective To compare the efficacy and safety of the continuation of trastuzumab or switching to TKI therapy in patients with brain metastases for trastuzumab therapy, so as to provide references for clinical treatment and improve the survival of patients with brain metastasis of HER2-positive breast cancer.
Methods A total of 74 breast cancer patients with brain metastases who were admitted to the Fifth Medical Center, Chinese PLA General Hospital from 2007 to 2021 were included in this study. Patients with brain metastasis who had previously received trastuzumab with stable extracranial lesions and new or progressive intracranial lesions were enrolled. One group of patients continued trastuzumab therapy (Cohort A), while the other group switched to TKI therapy (Cohort B). The primary endpoints were overall survival (OS) and intracranial progression-free survival (IC-PFS), and the secondary endpoints were intracranial objective response rate (ORR), intracranial clinical benefit rate (CBR), and safety. The follow-up ended in April 2022.
Results We enrolled 74 breast cancer patients with brain metastases, including 38 patients in the trastuzumab group and 36 patients in the TKI group. All patients were female, with a median age of 49.5 years and 44 years, respectively. The median DFS was 17 months and 16 months in the two groups, respectively (P>0.05). The median intracranial progression-free survival was 9 months and 8 months (P=0.400), and the median overall survival was 75 months and 96 months (P=0.140) in trastuzumab group and TKI group. The clinical response rate (ORR) was 23.7% and 41.7% (P=0.099), and the clinical benefit rate (CBR) was 63.2% and 75.0% (P=0.271) in the two groups. The incidence of grade III-IV adverse reaction of the trastuzumab group was 34.2% (13/38), and it was 41.7% (15/36) in the TKI group, without significant difference (P>0.05). No treatment-related death occurred.
Conclusion TKIs tend to prolong overall survival in patients with brain metastases who respond to trastuzumab, however, the difference is not significant.
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