[1684] Clincopathologic and Immunohistochemical Characteristics of Metastatic Breast Carcinoma to the Brain: A Neurosurgical Series of 59 Cases

SE Martin, KA Johnson, P Steeg, EM Hattab. Indiana University School of Medicine, Indianapolis, IN; National Cancer Institute, Bethesda, MD

Background: Metastatic breast cancer to the central nervous system (CNS) is second only to lung in frequency. Affected patients typically have advanced systemic disease by the time CNS involvement is manifested. Patients with triple negative primary breast cancer and those with Her2 amplification usually are at an increased risk for metastasis. Currently, therapeutic options are limited with surgery generally offered to those with solitary lesions, and prognosis is poor (20% one-year survival). Therefore, greater understanding of this disease and its risk factors is essential for improved clinical outcome.
Design: Fifty-nine cases of metastatic breast cancer to the CNS were identified. Two cohorts were created: one for which paraffin blocks from both the primary and the metastatic lesions were available (matched) and another for which only the metastasis was available (unmatched). Cases were evaluated for various demographic, clinical and pathologic parameters. Immunohistochemistry for ER, PR, Her2 and EGFR, and Her2 FISH analysis were performed. Survival data was assessed.
Results: Patients were overwhelmingly Caucasian (87%). The median age at diagnosis of the CNS metastasis was 56 years with an average latency of 32 months. Most metastases were supratentorial (60%). The vast majority of tumors were infiltrating ductal type with a high SBR score. 44% were triple negative, while 19% were ER/PR negative, but Her2 positive. Sixteen patients were assigned to the matched cohort, of which 11 (69%) maintained an identical immunoprofile. Intense EGFR immunoreactivity was observed in a minority of cases and seemed to correlate with triple negative hormonal status. Follow-up interval ranged from 3 to 567 months, with a median follow-up of 57 months. At last follow-up, 25% of patients were still alive. The median overall survival from the time of diagnosis of CNS metastasis was 14 months.
Conclusions: The majority of solitary breast cancer metastases to the CNS were supratentorial, of the infiltrating ductal type, and either triple negative or ER/PR negative-Her2 positive. In at least two-thirds of the cases, the immunoprofile of the metastatic lesion was predictive of that of the primary tumor. Loss of ER or PR expression occurred in the remaining cases. In general, patients experienced poor clinical outcome; however, multivariate analysis of various clinical, pathologic and immunohistochemical characteristics is underway.
Category: Neuropathology

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 233, Tuesday Afternoon

 

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