Immune system-tumour efficiency ratio as a new oncological index for radiotherapy treatment optimization

Abstract

A dynamical system model for tumour-immune system interaction together with a method to mimic radiation therapy are proposed. A large population of virtual patients is simulated following an ideal radiation treatment. A characteristic parameter, the immune system-tumor efficiency ratio (ISTER) is introduced. ISTER dependence of treatment success and other features are studied. Radiotherapy treatment dose optimization, following ALARA (As Low As Reasonably Achievable) criterion, as well as a patient classification are drawn from the statistics results.

Radioterapia y el papel del sistema inmunitario

“…As expected, for each value of N we obtained similar results as obtained in [1]. Furthermore, when a fixed value of the ISTER is taken, the surface represented in figure 2 is obtained.…”

“…As shown in [1], the long term survival of patients will not improve with higher doses of radiation, on the contrary, it is possible to get the maximum success probability for our reference protocol at intermediate doses. Our model predicts that higher doses do not improve therapy outcomes.…”

“…A reference protocol was simulated in [1] while coefficients entering equation 3 were varied at random among admissible values [11]. The simulation, then, covers a wide range of tumors and supply general results useful to clinical practice.…”

“…Defining the probability of treatment success (Ps) as the fraction of "virtual patients" with no tumor at the end of treatment, it could be represented as a function of tumor cell survival factor and the Immune System -Tumor Effciency Rate [1], (ISTER), defined as ISTER = /   .…”

“…The relevance of immune system tumor interaction in a radiotherapy treatment (RT) and the importance of its study have been highlighted in a previous work [1]. The role of immune system in tumor control has been described in [2] and widely discussed in further works [3][4][5][6][7][8].…”