Background: The incidence of brain metastases (BM) is apparently rising in patients with advanced breast cancer (ABC). We performed a case control study to define current features of breast cancer related to central nervous system (CNS) metastases.
Patients and methods: From March 1999 to May 2006, we identified 72 patients with symptomatic BM of breast cancer. A comparison group was randomly selected assigning to each case two patients with primary breast cancer and no BM, matched for year of diagnosis, age and tumour stage (pT status and nodal status).
Results: Cases had a significantly higher rate of negative estrogen receptors (ERs) (60% in cases vs. 29% in controls), negative progesterone receptors (PgRs) (79% vs. 43%), HER2/neu over expression (44% vs. 13%) and immunostaining for Ki-67 > or =20% (84% vs. 55%), with p-value <0.001 for all four parameters in univariate analyses. On multivariate analysis, HER2/neu over expression and Ki-67 -20% were independent predictive factors of brain relapse (Odds Ratio (OR) 2.55, 95% confidence intervals (CI) 1.10-5.94 and OR 2.97, 95% CI 1.01-8.73, respectively). Endocrine unresponsive tumours (both ER and PgR <10%) showed an increased risk of relapse with BM of borderline significance (OR 1.91, 95% CI 0.87-4.12).
Conclusion: Patients with ER and PgR negative tumours either with or without HER-2/neu over expression should be considered at higher risk of BM.