One of the most minimally invasive and promising medical treatments for early-stage breast cancer is radio frequency ablation (RFA). However, with RFA it is difficult to insert the needle into the cancer because of the needle deforms the organ and, therefore, displaces the cancer. To solve this problem, we have developed a novel approach called "palpation based needle insertion". to achieve precise needle insertion for the treatment of breast cancer. This paper focuses on the simulation validation of our novel approach. First, we explain how we use a palpation probe to develop our novel method of robot assisted needle insertion. Our assumption was that the palpation probe can detect the cancerous part from force information and, at the same time, reduce the displacement of the part by applying pressure on the breast tissues, which means that the palpation probe can be used to realize precise needle insertion. Next, we show how we developed the breast model and validated it by comparing the results of a numerical simulation and an in vitro experiment. Finally, we evaluated both "normal needle insertion" and "palpation based needle insertion" by carrying out numerical simulations. The simulation data showed that the needle insertion error L of "palpation based needle insertion" is smaller than that of "normal needle insertion". In short, these simulations confirmed the effectiveness of "palpation based needle insertion".