In this chapter, the authors discuss computational modeling regarding response to oncological surgery from a conceptual perspective. In particular, emphasis is placed on biomedical mechanistic models for predicting the clinical outcomes in the context of oncological surgery. The medical background of oncological surgery is briefly addressed; the understanding of variables involved in oncological surgery is highlighted; the fundamentals of different approaches 260for modeling oncological surgery are explained, and results to be expected from each model are discussed. Finally, a computational model of oncological surgery, which considers tumor growth, nutrient diffusion and immune system variables, is explained using the R programming language.