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.

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.