Evaluation of prevalence, number, and temporal changes of circulating tumor cells as assessed after 2 and 5 years of follow-up in patients with early breast cancer in the SUCCESS A study.

11042 Background: Recent studies revealed that temporal changes in circulating tumor cells (CTC) prevalence assessed before and immediately after adjuvant chemotherapy (CT) might indicate treatment response in early breast cancer (EBC). However, there is limited knowledge on CTC status one or more years after chemotherapy treatment. Here we present descriptive data on CTC status prospectively evaluated 2 and 5 years after primary diagnosis in the German SUCCESS A study. Methods: The SUCCESS A trial is a large, randomized, open-label, 2x2 factorial design Phase III study comparing disease free survival (DFS) in patients with EBC treated with 3 cycles of Epirubicin-Fluorouracil-Cyclophosphamide (FEC) followed by either 3 cycles of Docetaxel (D) or 3 cycles of Gemcitabine-Docetaxel (DG), and comparing DFS in patients treated with 2 years or 5 years of Zoledronate. CTC status at various time points was assessed using the FDA-approved CellSearch System (Veridex, USA). Results: Data on CTC status both at 2 year...