Mathematical modeling of tumor growth in mice following low-level direct electric current

A modification to the conventional Gompertz equation (named modified Gompertz equation) is introduced to describe the solid tumor growth perturbed with direct electric current. Simulations of this equation are made. Quantitative fitting criteria as goodness-of-fit, handling missing data and prediction capability are considered. Also, parameter estimation accuracy is calculated. A fit of the experimental data of Ehrlich and fibrosarcoma Sa-37 tumor growths treated with different intensities of direct electric current are also made to validate this modified Gompertz equation. The results obtained in this study corroborate that the direct electric current effectiveness depends on (i/i0) ratio, and also on the duration of the effects of it into the tumor, and of the tumor type. It was concluded that the modified Gompertz equation has a good prediction capability to describe both unperturbed and perturbed tumor growths and it could be used to help physicians choose the most appropriate treatment for patients and animals with malignant solid tumors.