The combination of radiation therapy and chemotherapy is rooted in its ability to help achieve locoregional and systemic control, therefore increasing the overall disease-free survival of patients. Understanding the mechanistic actions of cytotoxic agents and their targets on the cell cycle, as well as the governing pharmacokinetic principles can improve treatment delivery. The adjuvant treatment setting can overcome barriers such as hypoxia and genetically driven treatment resistance.

The purpose of this review is to present theoretical frameworks behind the chemoradiation paradigm and to describe current chemoradiation practices in radiation oncology.

A review was conducted using the US National Library of Medicine, National Institutes of Health database (PubMed) using the following search keywords: chemoradiation, spatial cooperation, chemotherapeutic agents, pharmacokinetics, anti-vascular agents, tumour vasculature and tumour hypoxia.

Current research has reported several rationales for the beneficial combination of radiation and chemotherapy to eradicate oncological diseases. Mechanisms of action and biological approaches are showing that concurrent treatments, as well as novel agents such as anti-vascular and anti-angiogenic agents may benefit improved treatment outcomes by reducing micro hypoxic environments in tumours. In addition, chemotherapy administered in tandem with radiation enhances cell-killing effects by targeting the cell cycle.