title: Effect of community population size on breast cancer screening, stage distribution, treatment use and outcomes.
abstract: OBJECTIVE
  Residents of rural communities have decreased access to cancer screening and treatments compared to urban residents, though use of resources and patient outcomes have not been assessed with a comprehensive population-based analysis. The objectives of this study were to investigate whether breast cancer screening and treatments were utilized less frequently in rural BC and whether this translated into differences in outcomes.
  
  
  METHODS
  All patients diagnosed with breast cancer in British Columbia (BC) during 2002 were identified from the Cancer Registry and linked to the Screening Mammography database. Patient demographics, pathology, stage, treatments, mammography use and death data were abstracted. Patients were categorized as residing in large, small and rural local health authorities (LHAs) using Canadian census information. Use of resources and outcomes were compared across these LHA size categories. We hypothesized that mastectomy rates (instead of breast-conserving surgery) would be higher in rural areas, since breast conservation is standardly accompanied by adjuvant radiotherapy, which has limited availability in rural BC. In contrast we hypothesized that cancer screening and systemic therapy use would be similar, as they are more widely dispersed across BC. Exploratory analyses were performed to assess whether disparities in screening and treatment utilization translated into differences in survival.
  
  
  RESULTS
  2,869 breast cancer patients were included in our study. Patients from rural communities presented with more advanced disease (p=0.01). On multivariable analysis, patients from rural, compared to urban, LHAs were less likely to be screening mammography attendees (OR=0.62; p<0.001). Women from rural communities were less likely to undergo breast-conserving surgery (multivariable OR=0.47; p<0.001). There was no significant difference in use of chemotherapy (p=0.54) or hormonal therapy (p=0.36). The 5-year breast cancer-specific survival for large, small and rural LHAs was 90%, 88% and 86%, respectively (p=0.08), while overall survival was 84%, 81% and 77%, respectively (p=0.01). On multivariable analysis with 7.4 years of median follow-up, neither breast cancer-specific survival (HR=1.16; 0.76-1.76; p=0.49) nor overall survival (HR=1.25; 0.92-1.70; p=0.16) was significantly worse for patients from rural compared to large LHAs.
  
  
  CONCLUSIONS
  There was a significant difference in screening mammography use, stage distribution and loco-regional treatments use by population size of LHA. After controlling for differences in patient and tumour factors by LHA, survival was not significantly different.
authors.affiliation: BC Cancer Agency, Centre for the North, Prince George, BC. rolson2@bccancer.bc.ca
authors.forename: Robert A
authors.initials: RA
authors.lastname: Olson
authors.forename: Alan
authors.initials: A
authors.lastname: Nichol
authors.forename: Nadine R
authors.initials: NR
authors.lastname: Caron
authors.forename: Ivo A
authors.initials: IA
authors.lastname: Olivotto
authors.forename: Caroline
authors.initials: C
authors.lastname: Speers
authors.forename: Stephen
authors.initials: S
authors.lastname: Chia
authors.forename: Ashley
authors.initials: A
authors.lastname: Davidson
authors.forename: Andy
authors.initials: A
authors.lastname: Coldman
authors.forename: Chris
authors.initials: C
authors.lastname: Bajdik
authors.forename: Scott
authors.initials: S
authors.lastname: Tyldesley
mesh_terms: D000970:Antineoplastic Agents; D001943:Breast Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D001955:British Columbia / Q000453:epidemiology; D003131:Combined Modality Therapy / Q000706:statistics & numerical data; D004363:Drug Utilization; D005260:Female; D006297:Health Services Accessibility; D006801:Humans; D008403:Mass Screening / Q000706:statistics & numerical data*; D008408:Mastectomy / Q000379:methods / Q000706:statistics & numerical data; D008875:Middle Aged; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D018714:Radiotherapy, Adjuvant / Q000706:statistics & numerical data; D019035:Rural Health Services / Q000706:statistics & numerical data*; D015996:Survival Rate
chemical_list: D000970:Antineoplastic Agents