title: Dosimetric comparison between proton beam therapy and photon radiation therapy for locally advanced non-small cell lung cancer.
abstract: OBJECTIVE
  To assess the feasibility of proton beam therapy for the patients with locally advanced non-small lung cancer.
  
  
  METHODS
  The dosimetry was analyzed retrospectively to calculate the doses to organs at risk, such as the lung, heart, esophagus and spinal cord. A dosimetric comparison between proton beam therapy and dummy photon radiotherapy (three-dimensional conformal radiotherapy) plans was performed. Dummy intensity-modulated radiotherapy plans were also generated for the patients for whom curative three-dimensional conformal radiotherapy plans could not be generated.
  
  
  RESULTS
  Overall, 33 patients with stage III non-small cell lung cancer were treated with proton beam therapy between December 2011 and August 2014. The median age of the eligible patients was 67 years (range: 44-87 years). All the patients were treated with chemotherapy consisting of cisplatin/vinorelbine or carboplatin. The median prescribed dose was 60 GyE (range: 60-66 GyE). The mean normal lung V20 GyE was 23.6% (range: 14.9-32%), and the mean normal lung dose was 11.9 GyE (range: 6.0-19 GyE). The mean esophageal V50 GyE was 25.5% (range: 0.01-63.6%), the mean heart V40 GyE was 13.4% (range: 1.4-29.3%) and the mean maximum spinal cord dose was 40.7 GyE (range: 22.9-48 GyE). Based on dummy three-dimensional conformal radiotherapy planning, 12 patients were regarded as not being suitable for radical thoracic three-dimensional conformal radiotherapy. All the dose parameters of proton beam therapy, except for the esophageal dose, were lower than those for the dummy three-dimensional conformal radiotherapy plans. In comparison to the intensity-modulated radiotherapy plan, proton beam therapy also achieved dose reduction in the normal lung. None of the patients experienced grade 4 or worse non-hematological toxicities.
  
  
  CONCLUSIONS
  Proton beam therapy for patients with stage III non-small cell lung cancer was feasible and was superior to three-dimensional conformal radiotherapy for several dosimetric parameters.
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.|Department of Radiation Oncology, Buddhist Tzu-Chi General Hospital, Hualien, Taiwan.
authors: Chen-Ta
authors: CT
authors: Wu
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Atsushi
authors: A
authors: Motegi
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Kana
authors: K
authors: Motegi
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Kenji
authors: K
authors: Hotta
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Ryosuke
authors: R
authors: Kohno
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Hidenobu
authors: H
authors: Tachibana
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Motoki
authors: M
authors: Kumagai
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Naoki
authors: N
authors: Nakamura
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Hidehiro
authors: H
authors: Hojo
authors: Department of Thoracic Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors: Seiji
authors: S
authors: Niho
authors: Department of Thoracic Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors: Koichi
authors: K
authors: Goto
authors: Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.
authors: Tetsuo
authors: T
authors: Akimoto
keywords: 3DCRT; IMRT; dosimetric analysis; locally advanced non-small cell lung cancer; proton beam therapy