A triple-variable Integral Equation for Tumor Control Cumulative Probability (TCCP) is developed with the addition of the important radiotherapy Treatment-Time parameter. Based on a previous double TCCP Integral Equation depending on Biological Model parameters (α , β ), the NEffective model is implemented in Tumor Control Probability (TCP) equation. Results comprise a TCCP Integral Equation model with three essential parameters for Radiation Therapy precise determination of TCCP. Solution shows the method to obtain a 3D Integral Equation of first kind. Results applications could involve better optimization for TCCP in radiotherapy biological models. Radiotherapy Treatment Planning Optimization (TPO) and Radioprotection consequences are explained.