**5. Remodeling, cellular aspects at the level of the extracellular matrix**

The influence of ionizing radiation at the tumor tissue and cell level and the processes of reducing the side effects of radiation are schematically represented in **Figure 2**.

At the top of the image are represented the four phases of the healing process of lesions produced by surgery or radiotherapy namely the phase of hemostasis, inflammatory phase, proliferative phase, and the remodeling phase.

At the bottom of the image are shown schematically the biological processes as a result of the action of radiation on the tumor DNA and due to double-stranded lesions that are irreversible, which finally facilitates the destruction of tumor cells by initiating the process of cell death called apoptosis. This explains how local tumor control is possible. Optimizing this process of tumor destruction and restoring the structures of the peritumoral tissue makes possible the remodeling process in which the healing process is present [6].

#### **Figure 2.**

*Schematic representation of radiation action at the tumor cell level (at the bottom) and of the remodeling and scarring process (at the top of the figure) [7].*

### *The Remodeling in Cancer Radiotherapy DOI: http://dx.doi.org/10.5772/intechopen.102732*

The role of the extracellular matrix and cellular regulators in the plasticity of tumor cells are schematically rendered in **Figure 3**. The destruction of the tumor following irradiation makes it possible to restore the basal membrane and sometimes even remodeling with restitutio ad integrum in the tumor bed is possible.

Tissue restoration ad integrum after the destruction of malignant tumor and restoration of the basal membrane is shown below [6].

#### **Figure 3.**

*Schematic representation of pathophysiological processes that demonstrate the cellular plasticity of tumor cells in the invasion process with tumor progression and metastasis (on the left side) [8] and restoration of the basal membrane and epithelium after tumor destruction by irradiation (on the right side).*
