Clinical features and course of brain metastases in triple-negative breast cancer: Comparison with HER2+ and other type

Abstract

1064 Background: Incidences and clinical aggressiveness of intracranial metastasis in triple negative (TN) breast cancer have not been well delineated compared to HER2+ subtype. Methods: Patients (pts) who were diagnosed with primary breast cancer at Asan Medical Center from January 1990 to July 2006 were screened (Lee SS, Breast Cancer Res Treat. 2008). All pts with brain metastases, identified by CT or MRI, were included and classified into three subtypes (TN, HER2+ and other). The clinical features and course of brain metastases with TN breast cancer, defined according to immunohistochemical staining and HER2 FISH analysis, were reanalyzed and compared among three groups. Results: Of 7,872 breast cancer pts, 198 pts developed brain metastases and 61 pts with unknown ER, PR, or HER2 status were excluded. Of 137 pts, incidences of TN, HER2+ and other group were 32% (44), 50% (69), and 18% (24), respectively. The median age at the time of brain metastases was 46 years (yr) (range 29–70 yr) in TN group, 48 yr (range 27–78 yr) in HER2 group, and 37 yr (range 25–62 yr) in other group with no significant difference. Clinical parameters such as performance status, previous adjuvant chemotherapy or radiotherapy, was similarly distributed among groups except that pts with earlier stages (I, II) were more prevalent in TN group compared to other two groups (59% vs 36% vs 38%, p = 0.01). With a median follow-up duration of 99 months (m), the median time from initial diagnosis of primary breast cancer to brain metastases was significantly shorter in TN group, compared with other two groups (TN, HER2, other; 20 m vs 32 m vs 45 m, p = 0.01) and the one from diagnosis of primary cancer to the first distant metastases at any sites was also shorter (16 m vs 23 m vs 23 m, p = 0.005). The median overall survival from diagnosis of primary cancer was significantly shorter in TN group (31 m vs 39 m vs 57 m, p = 0.02) and however, the one after brain metastases was not different among 3 groups (5.9 m vs 5.2 m vs 8.8 m, p = 0.31). Conclusions: TN breast cancer showed earlier brain metastases, earlier distant metastases at any sites and shorter overall survival in spite of high proportion of early stages, compared with other phenotypes. Preventive and therapeutic strategies of brain metastases in TN breast cancer are urgently needed. No significant financial relationships to disclose.