title: Relating acute esophagitis to radiotherapy dose using FDG-PET in concurrent chemo-radiotherapy for locally advanced non-small cell lung cancer.
abstract: OBJECTIVE
  To correlate radiotherapy (RT) dose to acute esophagitis (AE) by means of FDG-PET scans acquired after concurrent chemo-radiotherapy (cCRT) for locally advanced non-small-cell lung cancer (NSCLC).
  
  
  METHODS
  Patients treated with 24 × 2.75 Gy were selected on presence of a post-RT PET (PET(post)) scan acquired within 3 months after cCRT. The value of PET(post) in relation to AE was evaluated by comparing the mean esophageal SUV of the highest 50% (mathematical left angle bracket SUV(50%) mathematical right angle bracket) between gr < 2 and gr ≥ 2AE. The local dose on the esophagus wall was correlated to the SUV and modeled using a power-law fit. The Lyman-Kutcher-Burman (LKB) model was used to predict gr ≥ 2AE. The local dose-response relation was used in the LKB model to calculate the EUD. Resulting prediction accuracy was compared to D(mean), V(35), V(55) and V(60).
  
  
  RESULTS
  Eighty-two patients were included (gr < 2 = 25, gr ≥ 2=57). The mathematical left angle bracket SUV(50%) mathematical right angle bracket ≥ was significantly higher for gr ≥ 2AE (2.2 vs. 2.6, p < 0.01). The LKB parameters (95% CI) were n = 0.130 (0.120-0.141), m = 0.25 (0.13-0.85) and TD(50) = 50.4 Gy (37.5-55.4), which resulted in improved predictability of AE compared to other predictors.
  
  
  CONCLUSIONS
  Esophageal uptake of FDG post-cCRT reflects AE severity. Predictability of grade ≥ 2AE was improved by using the local dose-SUV response model, with narrow confidence intervals for the optimized LKB parameters.
authors.affiliation: Department of Radiation Oncoloyg, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors.forename: Jasper
authors.initials: J
authors.lastname: Nijkamp
authors.forename: Maddalena
authors.initials: M
authors.lastname: Rossi
authors.forename: Joos
authors.initials: J
authors.lastname: Lebesque
authors.forename: Jose
authors.initials: J
authors.lastname: Belderbos
authors.forename: Michel
authors.initials: M
authors.lastname: van den Heuvel
authors.forename: Margriet
authors.initials: M
authors.lastname: Kwint
authors.forename: Wilma
authors.initials: W
authors.lastname: Uyterlinde
authors.forename: Wouter
authors.initials: W
authors.lastname: Vogel
authors.forename: Jan-Jakob
authors.initials: JJ
authors.lastname: Sonke
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000628:therapy*; D059248:Chemoradiotherapy / Q000009:adverse effects*; D004307:Dose-Response Relationship, Radiation; D004941:Esophagitis / Q000209:etiology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18