title: Association between underestimation of tumour size by imaging and incomplete excision in breast-conserving surgery for breast cancer.
abstract: BACKGROUND
  Completeness of excision is the most important factor influencing local recurrence after breast-conserving surgery (BCS). The aim of this case-control study was to determine factors influencing incomplete excision in patients undergoing BCS.
  
  
  METHODS
  Women with invasive breast cancer treated by BCS between 1 June 2008 and 31 December 2009 were identified from a prospectively collected database in the Edinburgh Breast Unit. The maximum size of the tumour, measured microscopically, was compared with the size estimated before operation by mammography and ultrasound imaging. A multivariable analysis was performed to investigate factors associated with incomplete excision.
  
  
  RESULTS
  The cohort comprised 311 women, of whom 193 (62·1 per cent) had a complete (CE group) and 118 (40·7 per cent) an incomplete (IE group) excision. Mammography underestimated tumour size in 75·0 per cent of the IE group compared with 40·7 per cent of the CE group (P < 0·001). Ultrasound imaging underestimated tumour size in 82·5 per cent of the IE group compared with 56·5 per cent of the CE group (P < 0·001). The risk of an incomplete excision was greater when mammography or ultrasonography underestimated pathological size: odds ratio (OR) 4·38 (95 per cent c.i. 2·59 to 7·41; P < 0·001) for mammography, and OR 3·64 (2·03 to 6·54; P < 0·001) for ultrasound imaging. For every 1-mm underestimation of size by mammography and ultrasonography, the relative odds of incomplete excision rose by 10 and 14 per cent respectively.
  
  
  CONCLUSIONS
  Underestimation of tumour size by current imaging techniques is a major factor associated with incomplete excision in women undergoing BCS.
authors.affiliation: Edinburgh Breast Unit, University of Edinburgh, Edinburgh, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Dixon
authors.affiliation: Edinburgh University Medical School, University of Edinburgh, Edinburgh, UK.
authors.forename: C
authors.initials: C
authors.lastname: Newlands
authors.affiliation: South East Scotland Cancer Network, NHS Lothian, University of Edinburgh, Edinburgh, UK.
authors.forename: C
authors.initials: C
authors.lastname: Dodds
authors.affiliation: Edinburgh Breast Unit, University of Edinburgh, Edinburgh, UK.
authors.forename: J
authors.initials: J
authors.lastname: Thomas
authors.affiliation: Centre for Population Health Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: L J
authors.initials: LJ
authors.lastname: Williams
authors.affiliation: Edinburgh Breast Unit, University of Edinburgh, Edinburgh, UK.
authors.forename: I H
authors.initials: IH
authors.lastname: Kunkler
authors.affiliation: Edinburgh Breast Unit, University of Edinburgh, Edinburgh, UK.
authors.forename: A
authors.initials: A
authors.lastname: Bing
authors.affiliation: Department of Breast Surgery, Ninewells Hospital and Medical School, Dundee, UK.
authors.forename: E J
authors.initials: EJ
authors.lastname: Macaskill
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008327:Mammography; D000072662:Margins of Excision; D015412:Mastectomy, Segmental; D008875:Middle Aged; D015999:Multivariate Analysis; D018365:Neoplasm, Residual; D016217:Ultrasonography, Mammary