Conventional radiotherapy has shown its efficiency since decades with large progresses during the 1990s. However, for 15–20% of treated patients, there is no prognosis improvement either due to tumor radiation resistance and/or to side effects on normal tissues representing the limiting dose given during a radiotherapy protocol. A new modality of radiation therapy has emerged representing a technological breakthrough: hadrontherapy. This regroups mainly proton and carbon ion therapy. Dose deposit is in favor of hadrons compared to photons as it occurs at a precise depth in human body sparing upstream and downstream normal tissues. Mechanisms of action of photons and hadrons are different. When photons mainly act by water radiolysis—producing e−aq, H●, ●OH, H2O2, O2●−…, carbon ions and protons mainly act by direct effects, i.e. by direct transfer of ion energy to biological macromolecules. Moreover, efficiency of carbon ions is considered threefold higher (1.1 for protons) than X-rays in killing tumor cells, whereas it is considered lower for normal cells. These findings suggest strong advantages of hadrontherapy compared to conventional radiotherapy. However, some recent studies tend to show a stronger increase in oxidative stress in normal cells after protons or carbon ions than X-rays.
Part of the book: Novel Prospects in Oxidative and Nitrosative Stress