Proton radiotherapy in the treatment of lung cancer

Radiation therapy for lung cancer often leads to treatment-related pneumonitis or lung fibrosis, especially when given with concurrent chemotherapy. These side effects can impair quality of life and negatively affect treatment outcomes. With the advent of proton radiotherapy comes the possibility of reducing these toxicities by minimizing the amount of non-target tissue that is irradiated. Protons have significantly different physical characteristics that can make their use advantageous over standard photon radiotherapy. Multiple retrospective reviews and phase I/II studies have linked the use of protons with fewer side effects in at least some patients with lung cancer, and randomized trials comparing proton therapy with photon treatments are ongoing. Technologic advances may allow for even further minimization of toxicity associated with radiation therapy. In this review, we discuss the current state of proton therapy for the management of lung cancer as well as challenges and opportunities for further development of this treatment modality.