title: Regional Lymph Node Uptake of [(18)F]Fluorodeoxyglucose After Definitive Chemoradiation Therapy Predicts Local-Regional Failure of Locally Advanced Non-Small Cell Lung Cancer: Results of ACRIN 6668/RTOG 0235.
abstract: OBJECTIVE
  The American College of Radiology Imaging Network (ACRIN) 6668/Radiation Therapy Oncology Group (RTOG) 0235 study demonstrated that standardized uptake values (SUV) on post-treatment [(18)F]fluorodeoxyglucose-positron emission tomography (FDG-PET) correlated with survival in locally advanced non-small cell lung cancer (NSCLC). This secondary analysis determined whether SUV of regional lymph nodes (RLNs) on post-treatment FDG-PET correlated with patient outcomes.
  
  
  METHODS
  Included for analysis were patients treated with concurrent chemoradiation therapy, using radiation doses ≥60 Gy, with identifiable FDG-avid RLNs (distinct from primary tumor) on pretreatment FDG-PET, and post-treatment FDG-PET data. ACRIN core laboratory SUV measurements were used. Event time was calculated from the date of post-treatment FDG-PET. Local-regional failure was defined as failure within the treated RT volume and reported by the treating institution. Statistical analyses included Wilcoxon signed rank test, Kaplan-Meier curves (log rank test), and Cox proportional hazards regression modeling.
  
  
  RESULTS
  Of 234 trial-eligible patients, 139 (59%) had uptake in both primary tumor and RLNs on pretreatment FDG-PET and had SUV data from post-treatment FDG-PET. Maximum SUV was greater for primary tumor than for RLNs before treatment (P<.001) but not different post-treatment (P=.320). Post-treatment SUV of RLNs was not associated with overall survival. However, elevated post-treatment SUV of RLNs, both the absolute value and the percentage of residual activity compared to the pretreatment SUV were associated with inferior local-regional control (P<.001).
  
  
  CONCLUSIONS
  High residual metabolic activity in RLNs on post-treatment FDG-PET is associated with worse local-regional control. Based on these data, future trials evaluating a radiation therapy boost should consider inclusion of both primary tumor and FDG-avid RLNs in the boost volume to maximize local-regional control.
authors.affiliation: Mallinckrodt Institute of Radiology and Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Markovina
authors.affiliation: Department of Biostatistics and Center for Statistical Sciences, Brown University School of Public Health, Providence, Rhode Island.
authors.forename: Fenghai
authors.initials: F
authors.lastname: Duan
authors.affiliation: Center for Statistical Sciences, Brown University School of Public Health, Providence, Rhode Island.
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Snyder
authors.affiliation: Mallinckrodt Institute of Radiology and Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Barry A
authors.initials: BA
authors.lastname: Siegel
authors.affiliation: Department of Radiation Oncology, Case Western Reserve University, Cleveland, Ohio.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Machtay
authors.affiliation: Mallinckrodt Institute of Radiology and Alvin J. Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri. Electronic address: jbradley@radonc.wustl.edu.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Bradley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D059248:Chemoradiotherapy / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D049268:Positron-Emission Tomography / Q000379:methods; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D011879:Radiotherapy Dosage; D017211:Treatment Failure
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18