title: Protons safely allow coverage of high-risk nodes for patients with regionally advanced non-small-cell lung cancer.
abstract: Our objective was to determine if protons allow for the expansion of treatment volumes to cover high-risk nodes in patients with regionally advanced non-small-cell lung cancer. In this study, 5 consecutive patients underwent external-beam radiotherapy treatment planning. Four treatment plans were generated for each patient: 1) photons (x-rays) to treat positron emission tomography (PET)-positive gross disease only to 74 Gy (XG); 2) photons (x-rays) to treat high-risk nodes to 44 Gy and PET-positive gross disease to 74 Gy (XNG); 3) protons to treat PET-positive gross disease only to 74 cobalt gray equivalent (PG); and 4) protons to treat high-risk nodes to 44 CGE and PET-positive gross disease to 74 CGE (PNG). We defined high-risk nodes as mediastinal, hilar, and supraclavicular lymph nodal stations anatomically adjacent to the foci of PET-positive gross disease. Four-dimensional computed tomography was utilized for all patients to account for tumor motion. Standard normal-tissue constraints were utilized. Our results showed that proton plans for all patients were isoeffective with the corresponding photon (x-ray) plans in that they achieved the desired target doses while respecting normal-tissue constraints. In spite of the larger volumes covered, median volume of normal lung receiving 10 CGE or greater (V10Gy/CGE), median V20Gy/CGE, and mean lung dose were lower in the proton plans (PNG) targeting gross disease and nodes when compared with the photon (x-ray) plans (XG) treating gross disease alone. In conclusion, proton plans demonstrated the potential to safely include high-risk nodes without increasing the volume of normal lung irradiated when compared to photon (x-ray) plans, which only targeted gross disease.
authors: University of Florida, Proton Therapy Institute, Jacksonville, FL, USA. rnichols@floridaproton.org
authors: R C
authors: RC
authors: Nichols
authors: S H
authors: SH
authors: Huh
authors: B S
authors: BS
authors: Hoppe
authors: R H
authors: RH
authors: Henderson
authors: Z
authors: Z
authors: Li
authors: S
authors: S
authors: Flampouri
authors: H J
authors: HJ
authors: D'Agostino
authors: J D
authors: JD
authors: Cury
authors: D C
authors: DC
authors: Pham
authors: N P
authors: NP
authors: Mendenhall
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy*; D004947:Esophagus / Q000528:radiation effects; D056973:Four-Dimensional Computed Tomography; D006321:Heart / Q000528:radiation effects; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008198:Lymph Nodes; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D013116:Spinal Cord / Q000528:radiation effects; D014057:Tomography, X-Ray Computed; D011522:Protons
chemical_list: D011522:Protons