title: Shear-wave elastography contributes to accurate tumour size estimation when assessing small breast cancers.
abstract: OBJECTIVE
  To assess whether the size of peritumoural stiffness (PTS) on shear-wave elastography (SWE) for small primary breast cancers (≤15 mm) was associated with size discrepancies between grey-scale ultrasound (GSUS) and final histological size and whether the addition of PTS size to GSUS size might result in more accurate tumour size estimation when compared to final histological size.
  
  
  METHODS
  A retrospective analysis of 86 consecutive patients between August 2011 and February 2013 who underwent breast-conserving surgery for tumours of size ≤15 mm at ultrasound was carried out. The size of PTS stiffness was compared to mean GSUS size, mean histological size, and the extent of size discrepancy between GSUS and histology. PTS size and GSUS were combined and compared to the final histological size.
  
  
  RESULTS
  PTS of >3 mm was associated with a larger mean final histological size (16 versus 11.3 mm, p < 0.001). PTS size of >3 mm was associated with a higher frequency of underestimation of final histological size by GSUS of >5 mm (63% versus 18%, p < 0.001). The combination of PTS and GSUS size led to accurate estimation of the final histological size (p = 0.03). The size of PTS was not associated with margin involvement (p = 0.27).
  
  
  CONCLUSIONS
  PTS extending beyond 3 mm from the grey-scale abnormality is significantly associated with underestimation of tumour size of >5 mm for small invasive breast cancers. Taking into account the size of PTS also led to accurate estimation of the final histological size. Further studies are required to assess the relationship of the extent of SWE stiffness and margin status.
authors.affiliation: The Highland Breast Centre, Raigmore Hospital, Inverness, UK. Electronic address: russell.mullen@nhs.net.
authors.forename: R
authors.initials: R
authors.lastname: Mullen
authors.affiliation: Department of Breast Surgery, Ninewells Hospital, Dundee, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Thompson
authors.affiliation: Department of Breast Surgery, Ninewells Hospital, Dundee, UK.
authors.forename: O
authors.initials: O
authors.lastname: Moussa
authors.affiliation: Department of Breast Radiology, Ninewells Hospital, Dundee, UK.
authors.forename: S
authors.initials: S
authors.lastname: Vinnicombe
authors.affiliation: Department of Breast Radiology, Ninewells Hospital, Dundee, UK.
authors.forename: A
authors.initials: A
authors.lastname: Evans
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D047368:Tumor Burden / Q000502:physiology*; D016217:Ultrasonography, Mammary / Q000379:methods*