title: Population-based analysis of breast cancer treatment by intrinsic sub-type in Manitoba, Canada.
abstract: Few descriptive epidemiological studies on the incidence, treatment and survival can accurately reflect a whole population. Manitoba, Canada has an accurate cancer registry, a drug information program network and a breast screening program since 1995. This combined with a stable population provides true population data that can accurately describe the region.
  
  
  
  Using a retrospective cohort design all Breast Cancer cases were obtained from 2004-2010 (N=5399) and grouped by Intrinsic sub-type. Identifiable co-morbidities, prescribed endocrine therapy, staging, surgery, treatment and overall and disease-free survival by intrinsic sub-type were evaluated.
  
  
  
  Prevalence of Luminal A (41.7%), Luminal B HER2- (15.6%), Luminal B HER2+ (8.9%), Basal-like(10.8%), and HER2+ non-luminal (5.1%) were consistent with other descriptive studies in Canada and Spain. Over this time period the number of lumpectomies increased 1.7% per year (P=0.007). There was a steady increase of 3.4% per year in the use of aromatase inhibitors (P=0.005). Pre-menopausal patients had an increased proportion of HER2+ and Basal-like sub-types. The 7year overall/disease-free survival percentages for Luminal A, Luminal B HER2-, Luminal B HER2+, Basal-like, and HER2+ non-luminal were 88.7%/83.6, 78.2%/73.0, 81.5%/73.3%, 67.7%/63.2%, 70.4%/65.6% respectively.
  
  
  
  Reasons for variability in the prevalence of intrinsic sub-type by region is not fully understood. Manitoba is unique due the stability of the population, completeness of the registry and length of breast cancer screening program. Few true population-based studies grouped by intrinsic sub-type are available.
  
  
  
  Descriptive epidemiological studies guide future research by identifying factors that can affect treatment, recurrence, and survival.
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada.
authors: Elizabeth
authors: E
authors: Hammond
authors: CancerCare Manitoba, Canada.
authors: Emma
authors: E
authors: Shu
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada.
authors: Karagin
authors: K
authors: Sawchuk
authors: Research Institute in Oncology and Hematology, University of Manitoba/CancerCare Manitoba, Canada.
authors: Yvonne
authors: Y
authors: Myal
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada; Research Institute in Oncology and Hematology, University of Manitoba/CancerCare Manitoba, Canada.
authors: Afshin
authors: A
authors: Raouf
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada.
authors: Thomas
authors: T
authors: Klonisch
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada.
authors: Sabine
authors: S
authors: Hombach-Klonisch
authors: Research Institute in Oncology and Hematology, University of Manitoba/CancerCare Manitoba, Canada.
authors: Etienne
authors: E
authors: Leygue
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada.
authors: Sam
authors: S
authors: Kung
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada.
authors: Janice
authors: J
authors: Safneck
authors: Research Institute in Oncology and Hematology, University of Manitoba/CancerCare Manitoba, Canada.
authors: Michael
authors: M
authors: Mowat
authors: Research Institute in Oncology and Hematology, University of Manitoba/CancerCare Manitoba, Canada.
authors: Wayne
authors: W
authors: Xu
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada; Research Institute in Oncology and Hematology, University of Manitoba/CancerCare Manitoba, Canada.
authors: Leigh
authors: L
authors: Murphy
authors: Rady Faculty of Health Sciences, University of Manitoba, Canada; CancerCare Manitoba, Canada. Electronic address: marshall.pitz@umanitoba.ca.
authors: Marshall
authors: M
authors: Pitz
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000453:epidemiology / Q000378:metabolism / Q000473:pathology* / Q000628:therapy*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008350:Manitoba / Q000453:epidemiology; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000378:metabolism / Q000473:pathology* / Q000628:therapy*; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone
keywords: Breast cancer; Epidemiology; Intrinsic sub-type; Molecular sub-type; Population-based