Normal tissue effects and cytokine responses after fractionated X-ray or proton radiotherapy of the head and neck region in mice

Abstract

Proton therapy, a cutting-edge approach for treating head and neck cancers, shows promise in revolutionizing cancer treatment. Its key advantage lies in the unique physical properties of protons, which enable highly precise targeting of tumors while sparing the surrounding healthy tissues from radiation exposure minimizing potential side effects after cancer therapy. However, unlocking the full potential of proton therapy requires a deeper understanding of its biological effects on normal tissues, especially in comparison to conventional X-ray treatment. This is the first head and neck mouse study that directly compares radiation-induced normal tissue effects and cytokine response following X-ray and proton radiotherapy. The findings shed light on crucial aspects of normal tissue effects after radiation. The results indicate that protons exhibit a significantly higher relative biological effectiveness in normal tissues compared to the current clinical standard of 10%, which should be considered in the future proton therapy clinical trials with head and neck cancers. The study also uncovered a surprising lower cytokine response (signaling molecules) following proton therapy compared to X-rays. This highlights the importance of further investigating the mechanisms underlying immune and inflammatory responses induced by proton versus X-ray irradiation.