title: A prospective study on radiation pneumonitis following conformal radiation therapy in non-small-cell lung cancer: clinical and dosimetric factors analysis.
abstract: OBJECTIVE
  Clinical and dosimetric prognostic factors for radiation pneumonitis (RP) have been reported after three-dimensional conformal radiotherapy (3D-CRT) in patients with non-small cell lung cancer (NSCLC).
  
  
  METHODS
  Ninety-six patients who received 3D-CRT for stage IA to IIIB NSCLC were evaluated prospectively. Surgery was performed before radiation in 51% of the patients (n = 49). RP was diagnosed six-eight weeks after 3D-CRT using the Lent-Soma classification. Factors evaluated included treatment factors such as total mean lung dose (MLD), and dose-volume histogram (DVH) thresholds for several radiation dose steps. These thresholds were originally determined from the median of the irradiated lung volume at each step.
  
  
  RESULTS
  Six patients could not be evaluated for RP six weeks after 3D-CRT. Of the 90 remaining patients, 40 (44%) had RP (i.e. grade > or =1) at 6 weeks, including 7 patients (7.8%) with severe RP (grade > or =2). Regarding the whole toxicity (grade > or =1), age (> or =60 years), MLD, V20 and V30 were significantly related to RP. DVH thresholds determined for radiation doses from 20 to 40 Gy were also predictive of RP. Considering only severe RP (grade > or =2), only MLD, V20 and V30 remained associated with increased acute pulmonary toxicity.
  
  
  CONCLUSIONS
  In this study, dosimetric factors (MLD, V20, V30) and age (> or =60 years) were predictive of RP regarding the whole pulmonary toxicity (grade > or =1). In addition, thresholds from 20 to 40 Gy, based on a stratification according to the median of the percentage of irradiated lung volume, were also predictive factors. They may, therefore, help discriminate patients at high and low risk for RP. However, only MLD, V20 and V30 remained associated with severe RP (grade > or =2), probably due to the small number of severe events in our series.
authors.affiliation: Department of Radiation Oncology, Centre Léon Bérard-28, rue Laënnec 69373 Lyon Cedex 08, France.
authors.forename: Line
authors.initials: L
authors.lastname: Claude
authors.forename: David
authors.initials: D
authors.lastname: Pérol
authors.forename: Chantal
authors.initials: C
authors.lastname: Ginestet
authors.forename: Lionel
authors.initials: L
authors.lastname: Falchero
authors.forename: Dominique
authors.initials: D
authors.lastname: Arpin
authors.forename: Michel
authors.initials: M
authors.lastname: Vincent
authors.forename: Isabelle
authors.initials: I
authors.lastname: Martel
authors.forename: Stéphane
authors.initials: S
authors.lastname: Hominal
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Cordier
authors.forename: Christian
authors.initials: C
authors.lastname: Carrie
mesh_terms: D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005602:France; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D017564:Radiation Pneumonitis / Q000453:epidemiology* / Q000209:etiology; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D018570:Risk Assessment; D016019:Survival Analysis; D016896:Treatment Outcome