Breast cancer is the most common malignant tumor among women today. Available techniques for treating breast cancer often introduce strong side effects. The non-invasive electromagnetic ablation of breast tumors has a lot of potential, because it can provide a quick treatment modality without introducing harmful side effects. In this project we assess the feasibility of non-invasive electromagnetic ablation of female breast tumors. The two main challenges in this project are: 1. The computation of electromagnetic fields inside the female breast. 2. The focussing of power such that the power dissipated in the tumor is maximized while the power dissipated in healthy tissue is minimized. In our investigation we simulate a two-dimensional configuration with a circular array of line-sources operating at a single-frequency within the range of 1 to 10 GHz. The electromagnetic fields are computed using a discretized EFIE method, after which we evaluate three algorithms that focus the dissipated power in order to gain insight in the potential of this treatment modality.