Incidence of brain metastases in early stage HER2 3+ breast cancer patients; is there a role for brain CT in asymptomatic patients?

PURPOSE: Human epidermal growth factor receptor 2 overexpression (HER2 3+) is reported in retrospective studies as a factor that contributes to higher incidence of brain metastases (BM) in patients with metastatic breast carcinoma. Although there are some reports suggesting higher incidence of BM in adjuvant trastuzumab trials, the true incidence, as well as the time of occurrence of BM in early-stage high risk breast carcinoma patients, has not been widely prospectively explored. The main objective of this study was to prospectively explore the incidence of BM during and after adjuvant trastuzumab administration in HER2 3+ early-breast carcinoma patients. METHODS: Two hundred and fifty-eight patients with early, HER2 3+ breast carcinoma have been included in this analysis. Brain computed tomography (CT) scan was scheduled once during adjuvant trastuzumab therapy and thereafter only if central nervous system (CNS) symptoms occurred. RESULTS: Eighty-five patients (33%) underwent brain CT in the absence of CNS symptoms. The median number of trastuzumab cycles at the time of brain CT was 9 (range 4-18). There were no BM detected by brain CT in these 85 asymptomatic patients. However, during a median follow up of 18 months 5/258 patients (1.93%) developed BM, but only 2 (0.77%) while still receiving adjuvant trastuzumab. The median time from breast cancer diagnosis to BM was 24 months (range 14-43). CONCLUSION: BM are a rare event during adjuvant trastuzumab treatment and brain CT screening is not justified in asymptomatic patients with early HER2 3+ breast carcinoma.

Brain metastases as late breast cancer relapse. Single institution experience and review of the literature.

PURPOSE: Approximately 40% of HER2-positive breast cancer patients will develop brain metastases, usually during the first 2-3 years following initial diagnosis and up to 2 years after overt metastatic spread. However, there are no data about brain metastases development as a late disease relapse. In addition, there are no data whether the high incidence of brain metastases is maintained in patients with HER2 overexpression even in late brain metastases. The aim of this paper was to determine the incidence of brain metastases and the HER2 status in patients who developed late relapse, at least 5 years after the initial diagnosis. PATIENTS AND METHODS: Among 384 consecutive breast cancer patients with late relapse, only 8 developed brain metastases. Archival pathological specimens of the primary tumors of those 8 patients were tested by immunohistochemistry (IHC) for HER2 status. RESULTS: The incidence of late brain metastases was 2% (8/384). None of these patients had HER2 3+ primary breast cancer. CONCLUSION: This study shows that the risk for brain metastases in HER2 3+ breast cancer patients is very low or might be even absent as a late relapse. Absence of late brain metastases in HER2 3+ breast cancer might be attributed to specific biological characteristics of HER2 3+ carcinomas to develop brain metastases mostly in the early course of metastatic disease.