Wow, let's not jump to conclusions from Dr. Pateerson's extremely small study and say her2+ are more likely to develop brain mets. The study below is it not big enough to be stastically significant with only 6o her2+ study subjects. Anyway, I think her real point is not that her2+ more likely to develop brain mets, but given the treatment of Herceptin , which included most of the group, these study subjects still went on to develop brain mets.
Note, for a better study on the incidence of brain mets in her2+ bc, look at abstract #3020 Breast cancer phenotype associated with apropensity for CNS mets, from the SABC 2005. It suggests er,pr- and high grade is assoc. with brain mets, not her2+. This study was huge with thousands of women, indicating significance!!!!!!!!!!!!!!!!!!!
4086] Does HER2 positive breast cancer have a prelediction to metastasise to the brain?
Paterson C, McIntyre A, Canney PA. Beatson Oncology Centre, Western Infirmary, Glasgow, United Kingdom
Background: There have now been several reports of an increased rate of central nervous system (CNS) relapse in patients with metastatic HER2 positive tumours treated with Trastuzemab. However in one report CNS metastases occurred as frequently in patients with HER2 positive tumours but who had not been exposed to Trastuzemab [1], suggesting that CNS disease in these patients may not just be an effect of better control of systemic metastatic disease leading to longer survival. To investigate this further we have examined the rate of HER2 positivity in a sequential cohort of patients treated for brain metastases from breast cancer.
Material and Methods: Between April 2003 and October 2004 a cohort of 60 patients with a diagnosis of breast cancer who were treated with palliative radiotherapy for brain metastases were identified from the radiotherapy bookings system. A further 9 patients were excluded due other primary tumours. HER2 and ER status were obtained from the patient
s case records.
Results: 34/60 (57%) patients had HER2 positive breast cancers and 26/60 (43%) were HER2 negative. Of the patients with HER2 positive tumours 14 (41%) had not received Trastuzemab before developing their brain metastases. 13/34 patients (38%) with HER2 positive brain metastases were also ER positive, and 10/26 of patients with HER2 negative tumours (38%) were ER positive.
Discussion: The reported rate of HER2 positivity in the general population of breast cancer patients is between 20%
25%, less than half the rate in this series of patients with brain metastases. In contrast the rate of ER positivity in this group of patients was lower than expected and not related to the HER2 status. These results suggest that the high rate of brain metastases in HER2 positive patients is an intrinsic feature of the disease not just an effect of better control of systemic metastases by Trastuzemab.
1. Lai et al. Cancer. 101(4):810-6, 2004.
Saturday, December 10, 2005 7:00 AM