Targeting occult tumor cell dissemination in localised breast cancer

For the future, a better treatment of patients with breast cancer is dependent upon a better assessment of the individual risk of harbouring minimal residual disease after the completion of the surgical treatment. The aim is to separate very low risk pati ents from high risk patients for future metastasis, in order to reduce unnecessary treatment of the majority of very early staged breast cancer patients. Also, there is need for better identification of high risk patients that do not respond to the standa rd chemo- and/or hormonal therapy, and who needs to test more aggressive/alternative treatment. The project intends to approach these issues by 1) a detailed primary tumor analysis (gene-expression analysis and tissue micro array analysis) for selection o f clinically relevant genes and gene-products and 2) a further exploration and characterization of isolated tumor cells detected in the bone marrow, within a population of 873 patients treated for breast cancer with known clinical outcome status. The resu lts of the primary tumor analysis and analysis of the tumor cells in bone marrow (if present) will be correlated and associated to the disease recurrence status. This work will also include participation in the EU-supported project "Dismal". Furthermore, in a different study intended to include 1000 patients receiving standard chemotherapy after primary surgery, bone marrow analysis will be performed after completion of the standard chemotherapy for detection and characterization of remaining tumor cells. If present, the patients will receive additional chemotherapy of a different type (docetaxel), followed by further monitoring of bone marrow for tumor cells. The tumor- and recurrence status of patients with persistence and disappearance of tumor cells i n bone marrow cells will be compared, to predict the effect of the chemotherapy and to disclose the value of the bone marrow analysis as a surrogate marker for treatment response.