research on which breast cancer patients get CNS mets
 

1: Breast Cancer Res. 2006 Jul 17;8(4):R36 [Epub ahead of print] Links
Central nervous system relapse in patients with breast cancer is associated with advanced stages, with the presence of circulating occult tumor cells and with the HER2/neu status.

Souglakos J,
Vamvakas L,
Apostolaki S,
Perraki M,
Saridaki Z,
Kazakou I,
Pallis A,
Kouroussis C,
Androulakis N,
Kalbakis K,
Millaki G,
Mavroudis D,
Georgoulias V.
Department of Medical Oncology, University General Hospital of Heraklion, Crete, Greece. georgsec@med.uoc.gr.
ABSTRACT : INTRODUCTION : To evaluate the incidence of central nervous system (CNS) involvement in patients with breast cancer treated with a taxane-based chemotherapy regimen and to determine predictive factors for CNS relapse. METHODS : The medical files of patients with early breast cancer (n = 253) or advanced stage breast cancer (n = 239) as well of those with other solid tumors (n = 336) treated with or without a taxane-based chemotherapy regimen during a 42-month period were reviewed. HER2/neu overexpression was identified by immunohistochemistry, whereas cytokeratin 19 (CK-19) mRNA-positive circulating tumor cells (CTCs) in the peripheral blood were identified by real-time PCR. RESULTS : The incidence of CNS relapse was similar in patients suffering from breast cancer or other solid tumors (10.4% and 11.4%, respectively; P = 0.517). The incidence of CNS relapse was significantly higher in breast cancer patients with advanced disease (P = 0.041), visceral disease and bone disease (P = 0.036), in those who were treated with a taxane-containing regimen (P = 0.024), in those with HER2/neu-overexpressing tumors (P = 0.022) and, finally, in those with detectable CK-19 mRNA-positive CTCs (P = 0.008). Multivariate analysis revealed that the stage of disease (odds ratio, 0.23; 95% confidence interval, 0.007-0.23; P = 0.0001), the HER2/neu status (odds ratio, 29.4; 95% confidence interval, 7.51-101.21; P = 0.0001) and the presence of CK-19 mRNA-positive CTCs (odds ratio, 8.31; 95% confidence interval, 3.97-12.84; P = 0.001) were independent predictive factors for CNS relapse. CONCLUSION : CNS relapses are common among breast cancer patients treated with a taxane-based chemotherapy regimen, patients with HER2/neu-positive tumor and patients with CK-19 mRNA-positive CTCs.

Brain tumours associated with HER2/neu status
 

The association between metastatic brain cancer & HER2/neu status has been attributed by several medical commentators to one or more of the following factors:
-if treatment is Herceptin alone, the brain is not protected due to the blood-
barrier preventing Herceptin from reaching lesions.
- with Herceptin fighting successfully extra cranial tumours,patients are living
longer NED which leaves more time for brain metastases to develop.
- HER2 positive cancer being in the category of agressive cancers is likely to
arise more frequently whenever it is not adequately prevented/treated.