Fractal Dimension and Universality in Avascular Tumor Growth

TL;DR

This paper presents a physical model explaining avascular tumor growth, capturing empirical growth patterns, fractal cell distributions, and universal behaviors across tumors and animals using a common growth equation.

Contribution

It introduces a microscopic interaction-based model that reproduces macroscopic tumor growth features and explains their universality through the Bertalanffy-Richards growth equation.

Findings

Reproduces exponential and power-law growth phases.

Captures fractal spatial distribution of tumor cells.

Shows universal growth behavior across different biological systems.

Abstract

The comprehension of tumor growth is a intriguing subject for scientists. New researches has been constantly required to better understand the complexity of this phenomenon. In this paper, we pursue a physical description that account for some experimental facts involving avascular tumor growth. We have proposed an explanation of some phenomenological (macroscopic) aspects of tumor, as the spatial form and the way it growths, from a individual-level (microscopic) formulation. The model proposed here is based on a simple principle: competitive interaction between the cells dependent on their mutual distances. As a result, we reproduce many empirical evidences observed in real tumors, as exponential growth in their early stages followed by a power law growth. The model also reproduces the fractal space distribution of tumor cells and the universal behavior presented in animals and tumor growth, conform reported by West, Guiot {\it et. al.}\cite{West2001,Guiot2003}. The results suggest that the universal similarity between tumor and animal growth comes from the fact that both are described by the same growth equation - the Bertalanffy-Richards model - even they does not necessarily share the same biophysical properties.