On strategies on a mathematical model for leukemia therapy

https://doi.org/10.1016/j.nonrwa.2011.02.027Get rights and content

Abstract

A mathematical model for leukemia therapy based on the Gompertzian law of cell growth is studied. It is assumed that the chemotherapeutic agents kill leukemic as well as normal cells.

Effectiveness of the medicine is described in terms of a therapy function. Two types of therapy functions are considered: monotonic and non-monotonic. In the former case the level of the effect of the chemotherapy directly depends on the quantity of the chemotherapeutic agent. In the latter case the therapy function achieves its peak at a threshold value and then the effect of the therapy decreases. At any given moment the amount of the applied chemotherapeutic is regulated by a control function with a bounded maximum. Additionally, the total quantity of chemotherapeutic agent which can be used during the treatment process is bounded too.

The problem is to find an optimal strategy of treatment to minimize the number of leukemic cells while at the same time retaining as many normal cells as possible.

With the help of Pontryagin’s Maximum Principle it was proved that the optimal control function has at most one switch point in both monotonic and non-monotonic cases for most relevant parameter values.

A control strategy called alternative is suggested. This strategy involves increasing the amount of the chemotherapeutical medicine up to a certain value within the shortest possible period of time, and holding this level until the end of the treatment.

The comparison of the results from the numerical calculation using the Pontryagin’s Maximum Principle with the alternative control strategy shows that the difference between the values of cost functions is negligibly small.

Section snippets

Statement of the problem

A number of mathematical models describing growth of the cancer cells have been proposed [1], [2]. We shall consider a mathematical model which describes the dynamics of leukemia based on Gompertzian law [3], [4], [5], [6].

Let m=m(t) be the number of the leukemic cells at the time t. We describe the dynamics of cancer cells growth (the external influences are not taken into account) by the following equation dmdt=rmlnmam,r,maR+ (constants) .

The solution of Eq. (1.1) is given by m(t)=exp{lnma(

Optimal control strategy

The most important results of this section are the following: in the case of the monotonic therapy functions of the form f(h)=λh1+h,λR+ and of the non-monotonic therapy functions of the form f(h)=λhexp(bh)λ,bR+, the control function u is a piecewise constant function with at most one switch point for the most relevant parameters. More precisely, it depends on the difference rnrl (see Theorem 1, Theorem 2).

The Hamiltonian of the system (1.11) has the following form [28]: H=ψ1(rll+γl+fl)+ψ2(

Alternative control strategy

Let f(h) be a monotonic function. We shall investigate the behavior of system (1.11) assuming now that u is a constant parameter such that 0uR¯,R¯R+.

The unique critical point of (1.11) is l=γl+fl(h)rl,n=γn+cael+fn(h)rn,h=uγh+ε(Lael+Naen).

It is easy to prove for ε=0 or a sufficiently small ε>0 that all eigenvalues of the Jacobian matrix of system (1.11) at the critical point are negative. Therefore, the steady-state of the system is stable for small values of ε.

It follows from the implicit

Numerical results

In this section we present some numerical results concerning optimal and alternative strategies for the leukemia therapy. All results are obtained for the same model parameters and constraints: rl=0.25,rn=0.25,γh=0.01,ca=3.7105, λl=4.0,λn=1.8,a1=4.0, a2=2.0, b1=0.01, b2=0.01R=1,Q=250, La=1010, Ln=1010,ε=0. The initial values N(0)=108,L(0)=1.8108 and Nˆ=2.7107 are chosen for all numerical calculations (Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5).

We use the iterated (successive) approximation

Conclusion

Mathematical modeling of leukemia therapy is a complex optimal control problem. The number of cells and the interaction between cells and chemotherapeutic agent are determined by certain nonlinear laws. The cumulative amount of chemotherapeutic agent which can be applied during the therapy, as well as the intensity of this application, is restricted by some prescribed values.

The chemotherapeutic agent destroys not only leukemic but normal cells too, and this is reflected in the asymmetric form

Acknowledgment

The authors thank A.S. Novozhilov for his valuable and constructive comments.

References (29)

  • R.P. Aranjo et al.

    A history of the study of solid tumour growth: the contribution of mathematical modeling

    Bull. Math. Biol.

    (2004)
  • E.K. Afenya

    Mathematical Models of Cancer and their Relevant Insights

  • C.L. Frenzen et al.

    A cell kinetics justification for Gompertz’s equation

    SIAM J. Appl. Math.

    (1986)
  • M. Gyllenberg et al.

    Quiescence as an explanation of Gompertzian tumor growth

    Growth Dev. Aging

    (1989)
  • Cited by (25)

    • Adaptive terminal and supertwisting sliding mode controllers for acute Leukemia therapy

      2022, Biomedical Signal Processing and Control
      Citation Excerpt :

      All controllers proposed in this research are analyzed with respect to the above mentioned properties and compared with DISMC controller proposed in [28]. As evident from literature, the design problem of adaptive control combined with terminal sliding mode scheme has not been applied for the control of acute leukemia therapy [14,15,28]. As compared to previously applied optimal control [14,15] and double integral sliding mode control [28], the reason for the design of adaptive terminal SMC and supertwisting SMC is to further improve the results that can result in fast recovery from the disease.

    • Double Integral sliding mode control of Leukemia Therapy

      2020, Biomedical Signal Processing and Control
    • Maximization of viability time in a mathematical model of cancer therapy

      2017, Mathematical Biosciences
      Citation Excerpt :

      The works [14–19,21,23,28–30,36–40] considered unconstrained problems of constructing therapy strategies (treatment protocols) that are optimal with respect to certain scalar criteria written in terms of the state variables. In [14–18,21,23,28–30], the optimal open-loop control laws were investigated by using Pontryagin’s principle and corresponding numerical techniques. Moreover, the multi-objective approach of [22] was based on a specific reduction of the original unconstrained two-criteria problem to some constrained problem with a single criterion.

    • Delay-induced oscillatory dynamics in humoral mediated immune response with two time delays

      2013, Nonlinear Analysis: Real World Applications
      Citation Excerpt :

      Mathematical modeling of the humoral immune response to cancer is the main interest here and we shall elucidate through mathematical modeling, the various aspects of the dynamical behavior of the complicated process of antibody mediated immune response to cancer. Though numerous authors have studied the interaction between cancerous cells and the cell mediated immune responses through mathematical modeling [1–11,15–38], very few have concentrated on humoral immune responses to cancer [20,22,27,39]. Dillman and Koziol [20] proposed and developed a mathematical model to study the effect of the infusion of monoclonal antibody T101 into patients with chronic lymphatic leukemia and cutaneous T-cell lymphoma on the quantitative analysis of a dose–time–cell survival curve.

    • Adaptive boundary layer double integral sliding mode controller design for leukemia therapy

      2023, International Journal of Adaptive Control and Signal Processing
    View all citing articles on Scopus
    View full text