Background: Brain metastases are frequently encountered in Her2 positive advanced breast cancer. It is still not clear, if trastuzumab treatment should be continued following their diagnosis. In this analysis we evaluated if trastuzumab was able to influence time to in-brain progression (TTP) and overall survival (OS). For this reason, we compared patients who continued on trastuzumab with a historical control group.
Patients and methods: Seventeen Her2 positive patients receiving whole brain radiotherapy for brain metastases and continuing on trastuzumab were identified. As historical control group, thirty-six patients treated before 2002 were identified from a breast cancer database. We performed a multivariate analysis (Cox regression) to explore which factors were potentially able to significantly influence TTP and OS.
Results: Median TTP was 6 months, range 1-33+ months. Median OS was 7 months, range 1-38 months. Seventeen patients received trastuzumab after WBRT. Factors associated with prolonged TTP were KPS (p = 0.001), and intensified local treatment (p = 0.004). A trend towards longer TTP was observed in patients treated with trastuzumab (p = 0.068). OS was significantly influenced by KPS (p < 0.001), and continued antibody therapy (p = 0.001).
Conclusion: Two parameters were significantly associated with prolonged OS: KPS and trastuzumab. While there was a trend towards prolonged TTP in patients with trastuzumab treatment after WBRT, this did not reach statistical significance. It appears therefore reasonable to suggest continuation of antibody therapy in patients with good performance status despite disease spreading to the brain. Concerning activity of trastuzumab in brain metastases themselves, no final conclusion is possible.