Proton therapy for non-small cell lung cancer: Current evidence and future directions

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. Radiation dose escalation can improve survival in NSCLC patients but is often limited by adverse effects. One promising radiotherapy modality is proton radiotherapy, which, because of its physical characteristics, delivers minimal exit dose beyond the target volume and thus results in better sparing of normal tissues than does photon radiotherapy. Passive-scattering proton therapy and intensitymodulated proton therapy have shown promise in the treatment of early-stage and locally advanced non-small cell lung cancer. However, more studies are needed to optimize proton therapy, particularly intensity-modulated proton therapy, to address motion and density changes and to guide appropriate patient selection.