This paper presents a novel model for tumor growth dynamics that incorporates the interactions between chemotherapy, tumor cells ( \( T \) ), and macrophages ( \( M1 \) and \( M2 \) ). To facilitate mathematical analysis, the system is reformulated into a dimensionless form. Explicit expressions for the tumor-free equilibrium, tumor-dominant equilibrium, and interior equilibrium are derived. Stability analysis of the interior equilibrium reveals the potential for a Hopf bifurcation. Numerical simulations complement the theoretical findings, validating the analytical results. The results demonstrate that chemotherapy is highly effective in significantly reducing tumor cell populations, underscoring its therapeutic potential. Finally, a sensitivity analysis of the model parameters explores the role of chemotherapy in tumor reduction and eradication, emphasizing its impact on tumor growth dynamics.
