title: Particle beam radiation therapy using carbon ions and protons for oligometastatic lung tumors.
abstract: BACKGROUND
  A study was undertaken to analyze the efficacy and feasibility of particle beam radiation therapy (PBRT) using carbon ions and protons for the treatment of patients with oligometastatic lung tumors.
  
  
  METHODS
  A total of 47 patients with 59 lesions who underwent PBRT for oligometastatic lung tumors between 2003 and 2011 were included in this study. Patient median age was 66 (range, 39-84) years. The primary tumor site was the colorectum in 11 patients (23.4%), lung in 10 patients (21.3%) and a variety of other sites in 26 patients (55.3%). Thirty-one patients (66%) received chemotherapy prior to PBRT. Thirty-three lesions were treated with 320-MeV carbon ions and 26 were treated with 150- or 210-Mev protons in 1-4 portals. A median total dose of 60 (range, 52.8-70.2) GyE was delivered at the isocenter in 8 (range, 4-26) fractions.
  
  
  RESULTS
  The median follow-up time was 17 months. The local control, overall survival and progression-free survival rates at 2 years were 79%, 54 and 27% respectively. PBRT-related toxicities were observed; six patients (13%) had grade 2 toxicity (including grade 2 radiation pneumonitis in 2) and six patients (13%) had grade 3 toxicity. Univariate analysis indicated that patients treated with a biologically equivalent dose of 10 (BED10) <110 GyE10, had a significantly higher local recurrence rate. Local control rates were relatively lower in the subsets of patients with the colorectum as the primary tumor site. No local progression was observed in metastases from colorectal cancer irradiated with a BED10 ≥ 110 GyE10. There was no difference in treatment results between proton and carbon ion therapy.
  
  
  CONCLUSIONS
  PRBT is well tolerated and effective in the treatment of oligometastatic lung tumors. To further improve local control, high-dose PBRT with a BED10 ≥ 110 GyE10 may be promising. Further investigation of PBRT for lung oligometastases is warranted.
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan. shazrina@med.kobe-u.ac.jp.
authors.forename: Nor Shazrina
authors.initials: NS
authors.lastname: Sulaiman
authors.forename: Osamu
authors.initials: O
authors.lastname: Fujii
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Demizu
authors.forename: Kazuki
authors.initials: K
authors.lastname: Terashima
authors.forename: Yasue
authors.initials: Y
authors.lastname: Niwa
authors.forename: Takashi
authors.initials: T
authors.lastname: Akagi
authors.forename: Takashi
authors.initials: T
authors.lastname: Daimon
authors.forename: Masao
authors.initials: M
authors.lastname: Murakami
authors.forename: Ryohei
authors.initials: R
authors.lastname: Sasaki
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Fuwa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D063193:Heavy Ion Radiotherapy / Q000379:methods*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D061766:Proton Therapy / Q000379:methods*