title: Factors predictive of treatment by Australian breast surgeons of invasive female breast cancer by mastectomy rather than breast conserving surgery.
abstract: BACKGROUND
  The National Breast Cancer Audit Database of the Society of Breast Surgeons of Australia and New Zealand is used by surgeons to monitor treatment quality and for research. About 60% of early invasive female breast cancers in Australia are recorded. The objectives of this study are: (1) to investigate associations of socio-demographic, health-system and clinical characteristics with treatment of invasive female breast cancer by mastectomy compared with breast conserving surgery; and (2) to consider service delivery implications.
  
  
  METHODS
  Bi-variable and multivariable analyses of associations of characteristics with surgery type for cancers diagnosed in 1998-2010.
  
  
  RESULTS
  Of 30,299 invasive cases analysed, 11,729 (39%) were treated by mastectomy as opposed to breast conserving surgery. This proportion did not vary by diagnostic year (p>0.200). With major city residence as the reference category, the relative rate (95% confidence limits) of mastectomy was 1.03 (0.99, 1.07) for women from inner regional areas and 1.05 (1.01, 1.10) for those from more remote areas. Low annual surgeon case load (<10) was predictive of mastectomy, with a relative rate of 1.08 (1.03, 1.14) when compared with higher case loads. Tumour size was also predictive, with a relative rate of 1.05 (1.01, 1.10) for large cancers (40+ mm) compared with smaller cancers (<30 mm). These associations were confirmed in multiple logistic regression analysis.
  
  
  CONCLUSIONS
  Results confirm previous studies showing higher mastectomy rates for residents of more remote areas, those treated by surgeons with low case loads, and those with large cancers. Reasons require further study, including possible effects of surgeon and woman's choice and access to radiotherapy services.
authors.affiliation: Cancer Australia, Sydney, Australia. roder@internode.on.net
authors.forename: David
authors.initials: D
authors.lastname: Roder
authors.forename: Helen
authors.initials: H
authors.lastname: Zorbas
authors.forename: James
authors.initials: J
authors.lastname: Kollias
authors.forename: Chris
authors.initials: C
authors.lastname: Pyke
authors.forename: David
authors.initials: D
authors.lastname: Walters
authors.forename: Ian
authors.initials: I
authors.lastname: Campbell
authors.forename: Corey
authors.initials: C
authors.lastname: Taylor
authors.forename: Fleur
authors.initials: F
authors.lastname: Webster
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001315:Australia; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000601:surgery*; D005260:Female; D006297:Health Services Accessibility / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008408:Mastectomy / Q000706:statistics & numerical data; D015412:Mastectomy, Segmental / Q000706:statistics & numerical data*; D008875:Middle Aged; D015999:Multivariate Analysis; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D012424:Rural Population / Q000706:statistics & numerical data; D018709:Statistics, Nonparametric; D047368:Tumor Burden; D014505:Urban Population / Q000706:statistics & numerical data