title: A multi-institutional study to assess adherence to lung stereotactic body radiotherapy planning goals.
abstract: OBJECTIVE
  A multi-institutional planning study was performed to evaluate the frequency that current guidelines established by Radiation Therapy Oncology Group (RTOG) protocols and other literature for lung stereotactic body radiotherapy (SBRT) treatments are followed.
  
  
  METHODS
  A total of 300 patients receiving lung SBRT treatments in four different institutions were retrospectively reviewed. The treatments were delivered using Linac based SBRT (160 patients) or image guided robotic radiosurgery (140). Most tumors were located peripherally (250/300). Median fractional doses and ranges were 18 Gy (8-20 Gy), 12 Gy (6-15 Gy), and 10 Gy (5-12 Gy) for three, four, and five fraction treatments, respectively. The following planning criteria derived from RTOG trials and the literature were used to evaluate the treatment plans: planning target volumes, PTVV 100 ≥ 95% and PTVV 95 ≥ 99%; conformality indices, CI100% < 1.2 and CI50% range of 2.9-5.9 dependent on PTV; total lung-ITV: V20Gy < 10%, V12.5Gy < 15%, and V5Gy < 37%; contralateral lung V5Gy < 26%; and maximum doses for spinal cord, esophagus, trachea/bronchus, and heart and great vessels. Populations were grouped by number of fractions, and dosimetric criteria satisfaction rates (CSRs) were reported.
  
  
  RESULTS
  Five fraction regimens were the most common lung SBRT fractionation (46%). The median PTV was 27.2 cm(3) (range: 3.8-419.5 cm(3)). For all plans: mean PTVV 100 was 94.5% (±5.6%, planning CSR: 69.8%), mean PTVV 95 was 98.1% (±4.1%, CSR: 69.5%), mean CI100% was 1.14 (±0.21, CSR: 79.1%, and 16.5% within minor deviation), and mean CI50% was 5.63 (±2.8, CSR: 33.0%, and 28.0% within minor deviation). When comparing plans based on location, peripherally located tumors displayed higher PTVV 100 and PTVV 95 CSR (71.5% and 71.9%, respectively) than centrally located tumors (61.2% and 57.1%, respectively). Overall, the planning criteria were met for all the critical structure such as lung, heart, spinal cord, esophagus, and trachea/bronchus for at least 85% of the patients.
  
  
  CONCLUSIONS
  Among the various parameters that were used to evaluate the SBRT plans, the CI100% and CI50% were the most challenging criteria to meet. Although the CSRs of organs at risk were higher among all cases, their proximity to the PTV was a significant factor.
authors.affiliation: Loyola University Medical Center, Maywood, Illinois 60153.
authors.forename: Andrew
authors.initials: A
authors.lastname: Woerner
authors.affiliation: Loyola University Medical Center, Maywood, Illinois 60153.
authors.forename: John C
authors.initials: JC
authors.lastname: Roeske
authors.affiliation: Loyola University Medical Center, Maywood, Illinois 60153.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Harkenrider
authors.affiliation: Edward Cancer Center, Naperville, Illinois 60540.
authors.forename: John
authors.initials: J
authors.lastname: Fan
authors.affiliation: Department of Radiation Oncology, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Bulent
authors.initials: B
authors.lastname: Aydogan
authors.affiliation: Department of Radiation Oncology, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Matthew
authors.initials: M
authors.lastname: Koshy
authors.affiliation: Advocate Christ Medical Center, Oak Lawn, Illinois 60453.
authors.forename: Robert
authors.initials: R
authors.lastname: Laureckas
authors.affiliation: Advocate Christ Medical Center, Oak Lawn, Illinois 60453.
authors.forename: Faisal
authors.initials: F
authors.lastname: Vali
authors.affiliation: Loyola University Medical Center, Maywood, Illinois 60153.
authors.forename: Maria
authors.initials: M
authors.lastname: Campana
authors.affiliation: Loyola University Medical Center, Maywood, Illinois 60153.
authors.forename: Murat
authors.initials: M
authors.lastname: Surucu
mesh_terms: D019983:Guideline Adherence / Q000706:statistics & numerical data*; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008175:Lung Neoplasms / Q000601:surgery; D058958:Organs at Risk; D017410:Practice Guidelines as Topic; D016634:Radiosurgery / Q000379:methods / Q000706:statistics & numerical data*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D065287:Robotic Surgical Procedures / Q000379:methods