Triple-negative and HER2-overexpressing breast cancers exhibit an elevated risk and an earlier occurrence of cerebral metastases.

PURPOSE

Evaluation of the influence of immunohistochemically defined breast cancer (BC) subtypes and other risk factors on the development of cerebral metastases (CM).

METHODS

Exploratory analysis of a hospital-based prospective tumour registry including all patients with primary BC treated in our EUSOMA breast unit between 1998 and 2006.

RESULTS

The study cohort contained 2441 patients, including 284 patients (11.6%) with triple-negative (oestrogen receptor (ER), progesterone receptor (PR) and HER2-negative) and 245 patients (10.1%) with HER2-overexpressing BC subtypes. Overall, 80 patients (3.3%) developed CM within a median follow-up period of 47 months, 19 (23.8%) of them with triple-negative and 19 (23.8%) with HER2-positive tumours. Therefore, 6.7% of all patients with triple-negative and 7.8% of patients with HER2-positive breast cancer developed CM. Multivariate analysis indicated that the highest risk for CM was triple-negative breast cancer. Further independent risk factors were: HER2-overexpression, early onset BC (age<50 years), and large tumour size (pT3/4). Among those patients developing CM, triple-negative BC showed the shortest interval between primary diagnosis and occurrence of CM with a median of 22 months, compared to 30 and 63.5 months in HER2-positive and ER+/HER2- BC, respectively. Survival after occurrence of CM did not differ among the subtypes.

CONCLUSION

Patients with triple-negative or HER2-positive BC have a higher risk for CM compared with patients bearing the ER+/HER2- phenotype and develop CM earlier in the course of disease. A risk profile for CM might help adjust surveillance in high risk populations and identify patients with a need for new treatment strategies.