title: Combined analysis of V20, VS5, pulmonary fibrosis score on baseline computed tomography, and patient age improves prediction of severe radiation pneumonitis after concurrent chemoradiotherapy for locally advanced non-small-cell lung cancer.
abstract: BACKGROUND
  We aimed to develop a more accurate model for predicting severe radiation pneumonitis (RP) after concurrent chemoradiotherapy for non-small-cell lung cancer.
  
  
  METHODS
  We retrospectively analyzed data from 122 patients with locally advanced non-small-cell lung cancer treated with concurrent chemoradiotherapy. Several dose-volume histogram metrics including absolute lung volume spared from a 5 Gy dose (VS5) were analyzed for an association with RP above NCI-CTC grade 3 (RP ≥ G3). Clinical factors including pulmonary fibrosis score (PFS) and pulmonary emphysema score on baseline chest computed tomography (CT) were also analyzed.
  
  
  RESULTS
  Fourteen patients (11.4%) developed RP greater than or equal to G3. On univariate analysis, all dose-volume histogram metrics, sex, and PFS on baseline CT were significantly (p < 0.05) associated with occurrence of RP greater than or equal to G3. Multivariate analysis revealed that V20 greater than or equal to 26%, VS5 less than 1500 cc, age greater than or equal to 68 years, and PFS on baseline CT greater than or equal to 2 were significant risk factors. Thus, we defined a new predictive risk score (PRS) that combines these factors. The cumulative incidence of RP greater than or equal to G3 at 12 months were 0%, 7.8%, 26.6%, and 71.4% when the PRS was 0, 3-5, 6-8, and 9-14, respectively (p < 0.001). This PRS was superior at predicting RP than both V20 and VS5 combined, or V20 alone by receiver operating characteristic analysis (area under the curve, 0.888 versus 0.779 versus 0.678).
  
  
  CONCLUSIONS
  V20, VS5, age, and PFS on baseline CT are independent and significant risk factors for occurrence of severe RP. Combining these factors may improve the predictability of severe RP.
authors.affiliation: Department of Radiation Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan. Electronic address: tsuk@mub.biglobe.ne.jp.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tsujino
authors.affiliation: Department of Diagnostic Radiology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hashimoto
authors.affiliation: Department of Thoracic Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Temiko
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Department of Radiation Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Eisaku
authors.initials: E
authors.lastname: Yoden
authors.affiliation: Department of Radiation Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Fujii
authors.affiliation: Department of Radiation Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Ota
authors.affiliation: Department of Thoracic Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Satouchi
authors.affiliation: Department of Medical Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Negoro
authors.affiliation: Department of Diagnostic Radiology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Adachi
authors.affiliation: Department of Radiation Oncology, Hyogo Cancer Center, Akashi, Hyogo, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Soejima
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D019540:Area Under Curve; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000532:radiotherapy*; D059248:Chemoradiotherapy / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011656:Pulmonary Emphysema; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging*; D012372:ROC Curve; D011829:Radiation Dosage; D017564:Radiation Pneumonitis / Q000209:etiology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015996:Survival Rate; D014057:Tomography, X-Ray Computed