title: Pre-radiotherapy FDG PET predicts radiation pneumonitis in lung cancer.
abstract: BACKGROUND
  A retrospective analysis is performed to determine if pre-treatment [18 F]-2-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) image derived parameters can predict radiation pneumonitis (RP) clinical symptoms in lung cancer patients.
  
  
  METHODS
  We retrospectively studied 100 non-small cell lung cancer (NSCLC) patients who underwent FDG PET/CT imaging before initiation of radiotherapy (RT). Pneumonitis symptoms were evaluated using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv4) from the consensus of 5 clinicians. Using the cumulative distribution of pre-treatment standard uptake values (SUV) within the lungs, the 80th to 95th percentile SUV values (SUV(80) to SUV(95) were determined. The effect of pre-RT FDG uptake, dose, patient and treatment characteristics on pulmonary toxicity was studied using multiple logistic regression.
  
  
  RESULTS
  The study subjects were treated with 3D conformal RT (n=23), intensity modulated RT (n=64), and proton therapy (n=13). Multiple logistic regression analysis demonstrated that elevated pre-RT lung FDG uptake on staging FDG PET was related to development of RP symptoms after RT. A patient of average age and V(30) with SUV(95)=1.5 was an estimated 6.9 times more likely to develop grade ≥ 2 radiation pneumonitis when compared to a patient with SUV(95)=0.5 of the same age and identical V(30). Receiver operating characteristic curve analysis showed the area under the curve was 0.78 (95% CI=0.69 - 0.87). The CT imaging and dosimetry parameters were found to be poor predictors of RP symptoms.
  
  
  CONCLUSIONS
  The pretreatment pulmonary FDG uptake, as quantified by the SUV(95), predicted symptoms of RP in this study. Elevation in this pre-treatment biomarker identifies a patient group at high risk for post-treatment symptomatic RP.
authors.forename: Richard
authors.initials: R
authors.lastname: Castillo
authors.forename: Ngoc
authors.initials: N
authors.lastname: Pham
authors.forename: Sobiya
authors.initials: S
authors.lastname: Ansari
authors.forename: Dmitriy
authors.initials: D
authors.lastname: Meshkov
authors.forename: Sarah
authors.initials: S
authors.lastname: Castillo
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Adenike
authors.initials: A
authors.lastname: Olanrewaju
authors.forename: Brian
authors.initials: B
authors.lastname: Hobbs
authors.forename: Edward
authors.initials: E
authors.lastname: Castillo
authors.affiliation: The University of Texas Health Science Center, Houston, TX, USA. tguerrero@mdanderson.org.
authors.forename: Thomas
authors.initials: T
authors.lastname: Guerrero
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography / Q000379:methods; D011379:Prognosis; D017564:Radiation Pneumonitis / Q000000981:diagnostic imaging*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019788:Fluorodeoxyglucose F18