title: Comparison of the effectiveness of radiotherapy with photons, protons and carbon-ions for non-small cell lung cancer: a meta-analysis.
abstract: OBJECTIVE
  To provide a comparison between radiotherapy with photons, protons and carbon-ions in the treatment of Non-Small-Cell Lung Cancer (NSCLC), performing a meta-analysis of observational studies.
  
  
  METHODS
  Eligible studies on conventional radiotherapy (CRT), stereotactic radiotherapy (SBRT), concurrent chemoradiation (CCR), proton therapy and carbon-ion therapy were searched through a systematic review. To obtain pooled estimates of 2- and 5-year disease-specific and overall survival and the occurrence of severe adverse events for each treatment modality, a random effects meta-analysis was carried out. Pooled estimates were corrected for effect modifiers.
  
  
  RESULTS
  Corrected pooled estimates for 2-year overall survival in stage I inoperable NSCLC ranged from 53% for CRT to 74% for carbon-ion therapy. Five-year overall survival for CRT (20%) was statistically significantly lower than that for SBRT (42%), proton therapy (40%) and carbon-ion therapy (42%). However, caution is warranted due to the limited number of patients and limited length of follow-up of the particle studies.
  
  
  CONCLUSIONS
  Survival rates for particle therapy were higher than those for CRT, but similar to SBRT in stage I inoperable NSCLC. Particle therapy may be more beneficial in stage III NSCLC, especially in reducing adverse events.
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), Maastricht University Medical Centre, 6200 MD Maastricht, The Netherlands. janneke.grutters@maastro.nl
authors.forename: Janneke P C
authors.initials: JP
authors.lastname: Grutters
authors.forename: Alfons G H
authors.initials: AG
authors.lastname: Kessels
authors.forename: Madelon
authors.initials: M
authors.lastname: Pijls-Johannesma
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ruysscher
authors.forename: Manuela A
authors.initials: MA
authors.lastname: Joore
authors.forename: Philippe
authors.initials: P
authors.lastname: Lambin
mesh_terms: D002244:Carbon; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D063193:Heavy Ion Radiotherapy; D020450:Heavy Ions / Q000009:adverse effects; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009367:Neoplasm Staging; D017785:Photons / Q000009:adverse effects / Q000627:therapeutic use*; D061766:Proton Therapy; D011522:Protons / Q000009:adverse effects
chemical_list: D011522:Protons; D002244:Carbon