title: Adaptive planning using positron emission tomography for locally advanced lung cancer: A feasibility study.
abstract: OBJECTIVE
  To evaluate the feasibility of adaptive planning using positron emission tomography-computed tomography (PET-CT) in locally advanced non-small cell lung cancer.
  
  
  METHODS
  Patients with locally advanced non-small cell lung cancer receiving definitive radiation therapy (RT) were eligible. Initial planning PET-CT was performed and a conventional RT plan (2 Gy/fraction to 60 Gy) was designed. A second planning PET-CT was obtained at ~50 Gy. Dose escalation to ~70 Gy for residual fludeoxyglucose-avid disease was pursued at the discretion of the treating oncologists. The primary endpoint was feasibility of adaptive planning using interim PET-CT. Normal tissue dose-volume parameters were calculated for both adaptive and simulated nonadaptive plans.
  
  
  RESULTS
  From 2012 to 2014, 33 eligible patients were enrolled and underwent planning PET-CT, 3 of which were found to have new distant metastases. Of 30 patients who initiated RT, interim PET-CT was obtained in 29. This showed complete response in 2 patients, partial response/stable disease in 24, and new distant metastases in 3. Selective dose escalation was performed in 17 patients. For those receiving a boost, the median gross tumor volumes pre-RT and at ~50 Gy were 78 mL and 29 mL, respectively (P = .01). Reasons for no dose escalation were normal tissue constraints (n = 3), poorly defined residual disease (n = 2), acute toxicity (n = 1), and refusal of further therapy (n = 1). Adaptive planning compared with a simulated nonadaptive approach allowed for significant dose reductions to the lungs, heart, and esophagus (all P < .01).
  
  
  CONCLUSIONS
  Adaptive planning using PET-CT was feasible and allows for significant dose reductions to normal tissues compared with traditional planning techniques.
authors.affiliation: Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina. Electronic address: christopher.kelsey@duke.edu.
authors.forename: Chris R
authors.initials: CR
authors.lastname: Kelsey
authors.affiliation: Department of Radiology, Division of Cardiothoracic Imaging, Duke University Medical Center, Durham, North Carolina.
authors.forename: Jared D
authors.initials: JD
authors.lastname: Christensen
authors.affiliation: Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina.
authors.forename: Junzo P
authors.initials: JP
authors.lastname: Chino
authors.affiliation: Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina.
authors.forename: Justus
authors.initials: J
authors.lastname: Adamson
authors.affiliation: Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, North Carolina.
authors.forename: Neal E
authors.initials: NE
authors.lastname: Ready
authors.affiliation: Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.
authors.forename: Bradford A
authors.initials: BA
authors.lastname: Perez
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D011880:Radiotherapy Planning, Computer-Assisted / Q000009:adverse effects / Q000379:methods*