title: Changes in Gross Tumor Volume and Organ Motion Analysis During Neoadjuvant Radiochemotherapy in Patients With Locally Advanced Pancreatic Cancer Using an In-House Analysis System.
abstract: OBJECTIVE
  During radiation treatment, movement of the target and organs at risks as well as tumor response can significantly influence dose distribution. This is highly relevant in patients with pancreatic cancer, where organs at risk lie in close proximity to the target.
  
  
  METHODS
  Data sets of 10 patients with locally advanced pancreatic cancer were evaluated. Gross tumor volume deformation was analyzed. Dose changes to organs at risk were determined with focus on kidneys both without adaptive radiotherapy compensation and with replanning based on weekly acquired computed tomography scans.
  
  
  RESULTS
  During irradiation, gross tumor volume changes between 0% and 26% and moves within a radius of 5 to 16 mm. Required maximal dose to organs at risk for kidneys can be met with the current practice of matching computed tomography scans during treatment and adjusting patient position accordingly. Comparison of the mean doses and V15, V20 volumes demonstrated that weekly replanning could bring a significant dose sparing of the left kidney.
  
  
  CONCLUSIONS
  Manual matching with focus on bony structures can lead to overall acceptable positioning of patients during treatment. Thus, tolerance doses of organs at risk, such as the kidneys, can be met. With adequate margins, normal tissue constraints to organs at risk can be kept as well. Adaptive radiotherapy approaches (in this case with weekly rescanning) reduced dose to organs at risk, which may be especially important for hypofractionated approaches.
authors.affiliation: Department of Radiation Oncology, Technische Universität München (TUM), Munich, Germany kerstin.kessel@tum.de.
authors.forename: Kerstin A
authors.initials: KA
authors.lastname: Kessel
authors.affiliation: Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Heidelberg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Jäger
authors.affiliation: Department of Radiation Oncology, Technische Universität München (TUM), Munich, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Habermehl
authors.affiliation: German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Heidelberg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Rüppell
authors.affiliation: German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Heidelberg, Germany Department of Medical Informatics, Heilbronn University, Heilbronn, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Bendl
authors.affiliation: Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany German Cancer Research Center (DKFZ), Department of Medical Physics in Radiation Oncology, Heidelberg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Debus
authors.affiliation: Department of Radiation Oncology, Technische Universität München (TUM), Munich, Germany.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Combs
mesh_terms: D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D020360:Neoadjuvant Therapy; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D011880:Radiotherapy Planning, Computer-Assisted; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: IGRT; adaptive radiotherapy; intensity modulated radiotherapy; organ motion; pancreatic cancer; volume analysis