Neoadjuvant chemotherapy does not effect presence of micrometastases in bone marrow of breast cancer patients

Abstract

867 Background: The idea of adjuvant systemic therapy in breast cancer patients is to eliminate occult tumor cells which may already disseminate at a very early stage. The presence of occult tumor cells in bone marrow of breast cancer patients without evidence for clinically relevant metastatic disease is associated with worse overall and disease-free survival. However, it is unclear whether cytostatics may eliminate those occult tumor cells. Methods: Bone marrow aspirates obtained during surgery in breast cancer patients with locally resticed disease without evidence of a metastatic tumor cell spread were immunohistochemically stained with anti-cytokeratin antibodies in order to detect disseminated tumor cells. In a matched pair analysis bone marrow results of patients receiving neoadjuvant chemotherapy were matched with patients undergoing surgery first followed by adjuvant therapy. Results: Thirtyfour patients receiving neoadjuvant CTx were included into the analysis and matched for clinical stage and age with 34 breast cancer patients undergoing primary surgery. Detection rate of micrometastases was 23 out of 34 in the neoadjuvant group compared to 13 out of 34 in patients receiving surgery first followd by adjuvant therapy. Both groups did not significantly differ in clincal stage, age or bone marrow status. Interestingly, in 2 patients receiving trastuzumab in a neoadjuvant setting, no disseminated tumor cells were detected after systemic therapy. Conclusions: Our results suggest, that bone marrow status - which is highly correlated to survival - is not affected by cytostatic therapy. Therefore, adjuvant therapies in patients with micrometastases in bone marrow may include additional strategies in order to specifically target cells of a minimal residual disease. No significant financial relationships to disclose.