title: Effect of accurate heart delineation on cardiac dose during the CONVERT trial.
abstract: OBJECTIVE
  This study investigated the effect of deviation from protocol in heart delineation for the Concurrent Once-daily Versus twice-daily Radiotherapy (CONVERT) Trial ( ClinicalTrials.gov Identifier NCT00433563) quality assurance (QA) programme and the effect of that on mean cardiac dose and percentage of heart volume receiving ≥5 Gy (V5%) and percentage of heart volume receiving ≥30 Gy (V30%).
  
  
  METHODS
  Patients with limited-stage small-cell lung cancer in the CONVERT trial were randomized to receive 45 Gy in 30# twice daily or 66 Gy in 33# once daily radiotherapy, with concurrent chemotherapy in both arms. Of the 100 trial patient cases reviewed by the QA team [for patient selection, disease/organs at risk (OARs) outlining and treatment planning], 50 patient cases were selected, and the heart was reoutlined according to the "gold standard" trial protocol. Dose-volume histogram (DVH) data were extracted. The impact of change in heart volume on cardiac DVH is presented.
  
  
  RESULTS
  For gold standard cardiac outlines, an increase in V5%and V30%was seen in 77.3% and 81.8% of cases, respectively, in the control arm (45 Gy) and in 78.6% and 82.1% of cases, respectively, in the experimental arm (66 Gy). The median increase in V5%was 1.4% and in V30%, it was 3.4%. The average of the mean cardiac dose for the control arm increased by 2.1 Gy (from 15.2 Gy for the centres outline to 17.3 Gy for the gold standard outline) and for the experimental arm by 2.4 Gy (from 16.2 to 18.6 Gy).
  
  
  CONCLUSIONS
  This study demonstrates the importance of having a robust QA programme in place to ensure accuracy of cardiac delineation to facilitate future studies investigating the impact of cardiac dose on toxicity. Advances in knowledge: This study highlights the importance of ensuring accurate delineation of OARs in clinical trials, where conclusions about normal tissue toxicity are to be drawn.
authors.affiliation: 1 Department of Radiotherapy Physics, Mount Vernon Cancer Centre, Northwood, UK.
authors.forename: Nicki
authors.initials: N
authors.lastname: Groom
authors.affiliation: 2 Department of Radiotherapy, University College London Hospitals NHS Foundation Trust, London, UK.
authors.forename: Elena
authors.initials: E
authors.lastname: Wilson
authors.affiliation: 3 University of Manchester, Manchester Academic Health Science Centre, Institute of Cancer Sciences, Manchester, UK.|Radiotherapy Related Research, The Christie NHS Foundation Trust, Manchester, UK.
authors.forename: Corinne
authors.initials: C
authors.lastname: Faivre-Finn
mesh_terms: D006321:Heart / Q000033:anatomy & histology* / Q000528:radiation effects*; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy; D058958:Organs at Risk; D011879:Radiotherapy Dosage; D055752:Small Cell Lung Carcinoma / Q000532:radiotherapy