21085 Background: The impact of circulating tumor cells (CTC) in patients with primary breast cancer is still unclear. Primary systemic treatment (PST) allows the assessment of therapeutic efficacy in breast cancer patients without long follow-up periods. Here we present first results on the presence of CTC in peripheral blood of patients enrolled in the “GeparQuattro” study. Methods: This study incorporates three different chemotherapy approaches and additional Trastuzumab (Herceptin®) treatment for patients with HER-2/neu-positive tumors. Recruitment finished in November 2006 and not all patients have completed therapy yet. We used the CellSearch™ system to evaluate CTC before PST from 245 patients and after PST from 67 patients. CTC from 45 samples were also examined for HER-2/neu expression by immunocytochemistry in the CellSearch™ system. Results: Before PST we detected CTC in 54/245 patients (22%). CTC numbers in 7.5 mL blood ranged between 1 and 200 (mean 6.5). In 8 CTC-positive samples (3.3%) = 5 CTC were found. Her-2/neu-positive CTC were observed in 25/45 cases (55.6%). CTC could be detected in 7/67 patients (10.4%) after PST (1 or 2 CTC). Before and after PST blood was analyzed from 43 patients, 27 of them were CTC-negative at both time points. Ten initially CTC-positive cases were CTC-negative after PST whereas 6 cases were detected CTC-positive after PST although no CTC could be found before PST. Conclusions: With the CellSearch™ system CTC can be detected in non-metastatic breast cancer patients at primary diagnosis and also after PST. To our knowledge, this is the largest study evaluating the presence of CTC in this context. With the availability of response information from more patients, it will be possible to examine the correlation between the incidence of CTC and response as well as kinetics of HER-2/neu expression during Trastuzumab treatment. [Table: see text]
EpCAM-independent isolation of circulating tumor cells with epithelial-to-mesenchymal transition and cancer stem cell phenotypes using ApoStream® in patients with breast cancer treated with primary systemic therapy
