title: Predictors of breast radiotherapy plan modifications: quality assurance rounds in a large cancer centre.
abstract: OBJECTIVE
  This study describes the process and outcomes of breast radiotherapy (RT) quality assurance (QA) rounds, seeking to identify variables associated with plan modifications.
  
  
  METHODS
  Real-time data were prospectively collected over 2 years. Descriptive statistics determined the proportion of cases requiring no (A), minor (B), or major (C) modifications, which were then subjected to univariate and multivariate analyses.
  
  
  RESULTS
  A total of 2223 breast cancer QA cases were reviewed; 47 cases (2.1%) underwent a minor, and 52 cases (2.3%) required a major modification. Common changes included boost, volume, seroma, and bolus. On univariate analysis, regional nodal irradiation (RNI), tumour size, and axillary node dissection were significantly associated with major modifications. Upon multivariate analysis, the only independent predictor was RNI (OR 2.12, p=0.0075). For patients with no RNI, <2 cm tumours, no axillary lymph node dissection, and no boosts (n=420); the likelihood of category C was only 1.4%.
  
  
  CONCLUSIONS
  It is feasible to conduct QA review for all breast cancer cases prior to commencing RT. Patients undergoing RNI had a higher likelihood of plan modifications; a group with low risk of modification was identified, which could direct future re-structuring of QA rounds.
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
authors.forename: Timothy
authors.initials: T
authors.lastname: Lymberiou
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
authors.forename: Susanne
authors.initials: S
authors.lastname: Galuszka
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
authors.forename: Grace
authors.initials: G
authors.lastname: Lee
authors.affiliation: Division of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Fyles
authors.affiliation: Division of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
authors.forename: Susie
authors.initials: S
authors.lastname: Su
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada; Techna Institute, University Health Network, Toronto, Canada.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Purdie
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Pamela
authors.initials: P
authors.lastname: Catton
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Chung
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Dinniwell
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Anne
authors.initials: A
authors.lastname: Koch
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Wilfred
authors.initials: W
authors.lastname: Levin
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Lee
authors.initials: L
authors.lastname: Manchul
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Padraig
authors.initials: P
authors.lastname: Warde
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada. Electronic address: Fei-Fei.Liu@rmp.uhn.on.ca.
authors.forename: Fei-Fei
authors.initials: FF
authors.lastname: Liu
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D002173:Cancer Care Facilities / Q000458:organization & administration / Q000592:standards; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods; D008875:Middle Aged; D010347:Patient Care Planning / Q000458:organization & administration / Q000592:standards; D011446:Prospective Studies; D011785:Quality Assurance, Health Care
keywords: Breast cancer; Planning; Quality assurance; Radiotherapy