title: Is the use of a preoperative computed tomography beneficial to reduce the interobserver variability of the CTVboostdelineation for breast radiation therapy?
abstract: OBJECTIVE
  To determine whether the use of a preoperative (preop) computed tomography (CT) reduces (1) the clinical target volume boost (CTVboost) and (2) the interobserver variability (IOV) of the delineated CTVboostin breast radiation therapy.
  
  
  METHODS
  In patients treated with breast-conserving therapy, 3 CT scans in treatment position were performed: (1) preop; (2) after surgery, prechemotherapy (postop); and (3) postchemotherapy (postchemo). Six radiation-oncologists delineated the tumor bed and CTVboostbefore and after fusion of the preop CT. To assess the IOV, the Jaccard index was used. Linear mixed models were performedfor all analyses.
  
  
  RESULTS
  Eighty-two lumpectomy cavities were evaluated in 22 patients. No difference in CTVboostusing the fusion of the preop CT (50.0 cm3; 95% confidence interval [CI], 35.6-64.4) compared with no fusion (49.0 cm3; 95% CI, 34.6-63.4) (P = .6) was observed. A significant increase in IOV was shown with the fusion of the preop CT; the mean Jaccard index of the CTVboostdelineation of postop and postchemo CT together without the fusion of the preop CT was 0.53 (95% CI, 0.49-0.57) versus 0.50 (95% CI, 0.46-0.53) with fusion (P < .0001).
  
  
  CONCLUSIONS
  There is no benefit of using a preop CT to reduce the volume or the interobserver variability of the delineated CTVboostfor breast radiation therapy.
authors.affiliation: University Hospitals Leuven/KU Leuven, Department of Radiation-Oncology, Belgium. Electronic address: karolienverhoeven@msn.com.
authors.forename: Karolien
authors.initials: K
authors.lastname: Verhoeven
authors.affiliation: University Hospitals Leuven/KU Leuven, Department of Radiation-Oncology, Belgium.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Peeters
authors.affiliation: Iridium kankernetwerk Wilrijk, Department of Radiation-Oncology, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Erven
authors.affiliation: University Hospitals Leuven/KU Leuven, Department of Radiation-Oncology, Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Kindts
authors.affiliation: University Hospitals Leuven/KU Leuven, Department of Radiation-Oncology, Belgium.
authors.forename: Erik
authors.initials: E
authors.lastname: Van Limbergen
authors.affiliation: University Hospitals Leuven/KU Leuven, Department of Radiation-Oncology, Belgium.
authors.forename: Hilde
authors.initials: H
authors.lastname: Janssen
authors.affiliation: Catholic University Leuven, L-BioStat, Belgium.
authors.forename: Annouschka
authors.initials: A
authors.lastname: Laenen
authors.affiliation: University Hospitals Leuven/KU Leuven, Department of Radiation-Oncology, Belgium.
authors.forename: Saskia
authors.initials: S
authors.lastname: Petillion
authors.affiliation: University Hospitals Leuven/KU Leuven, Department of Radiation-Oncology, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Weltens
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D018270:Carcinoma, Ductal, Breast / Q000532:radiotherapy*; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D015588:Observer Variation; D011300:Preoperative Care; D000072378:Radiation Oncologists; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D018714:Radiotherapy, Adjuvant; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D014057:Tomography, X-Ray Computed