Effect of Neoadjuvant Radiation on Tumor Infiltrating T-cells by Low Dose Radiation in Colorectal Liver Metastases

The efficiency of T cell based immunotherapies is affected by the insufficient migration and activity of tumor specific effector T cells in the tumor. Aim of this phase I/II clinical trial is to evaluate whether a neoadjuvant, low dose radiotherapy can improve T cell connected anti tumor immune response in colorectal liver metastases. The primary endpoint is the number of tumor infiltrating T cells. Furthermore the T cell activity in situ, the number of regulatory T cells and the frequency of tumor reactive T cells in the blood and bone marrow will be examined.