title: Surgeon and breast unit volume-outcome relationships in breast cancer surgery and treatment.
abstract: OBJECTIVE
  To determine whether surgeon case volume and Unit case volume affected specific recognized key performance indicators (KPIs) of breast cancer surgical management.
  
  
  BACKGROUND
  An increasing body of evidence suggests that a higher standard of cancer care, demonstrated by improved outcomes, is provided in high-volume units or by high-volume surgeons. The volume-outcome relationship pertaining to screen-detected breast cancers has yet to be thoroughly established and remains a pertinent issue in view of the debate surrounding breast cancer screening.
  
  
  METHODS
  The study population comprised all women with a new screen diagnosed breast cancer between 2004-2005 and 2009-2010. Surgeons' mean annual patient volumes were calculated and grouped as very low (<5), low (5-15), medium (16-49), or high volume (>50). The effect of breast screening unit volume was also evaluated. Statistical analyses were performed using Minitab V16.0 software (State College, PA) and R V2.13.0.
  
  
  RESULTS
  There were 81,416 patients aged 61 (±6.8) years treated by 682 surgeons across 82 units. There were 209 very low-, 126 low-, 295 medium-, and 51 high-volume surgeons. The proportion of patients managed by very low-, low-, medium-, and high-volume surgeons was 1.2%, 6.9%, 65.5%, and 25.7%, respectively. Patients managed by high-volume surgeons were more likely to have breast-conserving surgery (BCS) than those managed by low-volume surgeons (P < 0.001). There was a higher proportion of sentinel lymph node biopsies (SLNB) performed by high-volume surgeons in invasive cancers (P = 0.005). High-volume units performed more BCS and SLNB than low-volume units (P < 0.001 and P < 0.001, respectively).
  
  
  CONCLUSIONS
  Even in a setting with established quality control measures (KPIs) surgeon and unit volume have potent influences on initial patient management and treatment.
authors.affiliation: *Discipline of Surgery, National University of Ireland, Galway, Ireland †West Midlands Cancer Intelligence Unit, University of Birmingham, UK ‡Department of Surgery, Royal Derby Hospital, Derby, UK §Department of Surgery, St James University Hospital, Leeds, UK ¶NHS Cancer Screening Programmes, Sheffield, UK.
authors.forename: Ailbhe M
authors.initials: AM
authors.lastname: McDermott
authors.forename: Deirdre M
authors.initials: DM
authors.lastname: Wall
authors.forename: Peadar S
authors.initials: PS
authors.lastname: Waters
authors.forename: Shan
authors.initials: S
authors.lastname: Cheung
authors.forename: Mark
authors.initials: M
authors.lastname: Sibbering
authors.forename: Kieran
authors.initials: K
authors.lastname: Horgan
authors.forename: Olive
authors.initials: O
authors.lastname: Kearins
authors.forename: Gill
authors.initials: G
authors.lastname: Lawrence
authors.forename: Julietta
authors.initials: J
authors.lastname: Patnick
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kerin
mesh_terms: D001943:Breast Neoplasms / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008408:Mastectomy / Q000379:methods*; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D018714:Radiotherapy, Adjuvant; D021701:Sentinel Lymph Node Biopsy; D016896:Treatment Outcome; D006113:United Kingdom; D016526:Workload