Image-Guided Proton Radiotherapy in Lung Cancer

Conventional photon radiotherapy with a dose of 60-66 Gy delivered in 30-33 fractions has been considered “standard” treatment for inoperable stage I/II/III non-small cell lung cancer (NSCLC). However, this dose regimen is associated with only 30-50% local control (1-3). Uncontrolled locoregional disease is a major source of continuous seeding to distant organs and is the eventual cause of treatment failure; thus, its eradication is essential for cure. Increasing clinical evidence suggests that a radiation dose-response relationship is involved in both survival and local control in patients with NSCLC (4-6). However, higher radiation doses, particularly with concurrent chemotherapy, are associated with higher levels of toxicity (7).