Canadian Journal of Public Health

, Volume 101, Issue 1, pp 101–105 | Cite as

Detection of Later Stage Breast Cancer in First Nations Women in Ontario, Canada

  • Amanda J. SheppardEmail author
  • Anna M. Chiarelli
  • Loraine D. Marrett
  • Lucia Mirea
  • E. Diane Nishri
  • Maureen E. Trudeau
  • the Aboriginal Breast Cancer Study Group
  • Norman Boyd
  • Paul Ferner
  • Amanda Hey
  • Caroline Lidstone-Jones
  • Yolanda Madarnas
  • Alison McMullen
  • John Shaw
  • Carol Rand
  • Vincent Young
Quantitative Research 2009 2009 Student Award Winner



To compare the distribution of stage at breast cancer diagnosis between First Nations (FN) and non-FN women, and to investigate factors associated with later diagnosis in FN women.


A case-case design was employed to compare FN women (N=287) to a frequency-matched random sample of women (N=671) from the general population diagnosed with breast cancer in the Ontario Cancer Registry. Women were matched (2:1) on period of diagnosis (1995–1999, 2000–2004), age at diagnosis (<50 vs. ≥50), and Regional Cancer Centre (RCC). Stage and data relevant to the determinants of stage were collected from medical charts at the RCCs. The association between stage (stage II+ vs. I) and FN status was modeled using logistic regression analyses; for FN women, the association between risk factors and stage was examined.


FN women (66%) were diagnosed with a later stage significantly more often than non-FN women (56%). FN women with a non-screened cancer (OR 5.03, 95% CI 2.48–10.21) and those who were overweight or obese (OR 2.98, 95% CI 1.27–6.98 and OR 4.46, 95% CI 1.95–10.21, respectively) were significantly more likely to be diagnosed at a later stage. Having a comorbidity reduced the odds of a later stage (OR 0.51, 95% CI 0.27–0.96) in FN women.


This study demonstrates the need for FN women, in particular those who are not accessing the health care system, to participate in breast screening programs aimed at detecting breast cancers earlier with a better prognosis. These findings suggest that the cancer care system in Ontario should better target this population through increasing awareness and access to screening.


Breast neoplasms diagnosis risk factors Indigenous population Ontario 



Comparer la répartition des stades du cancer du sein au moment du diagnostic entre les femmes membres des Premières nations (PN) et les femmes qui n’en sont pas membres (non-PN), et étudier les facteurs associés au diagnostic tardif chez les femmes des PN.


Nous avons mené une étude cas-cas pour comparer les femmes des PN (n=287) à un échantillon aléatoire apparié selon la fréquence, composé de femmes (n=671) de la population générale ayant un diagnostic de cancer du sein selon le Registre d’inscription des cas de cancer de l’Ontario. Les femmes ont été appariées (2:1) selon la période du diagnostic (1995–1999, 2000–2004), l’âge au diagnostic (<50 ans ou ≥50) et le Centre régional de cancérologie (CRC). Le stade et les données liées aux déterminants du stade ont été obtenus dans les dossiers médicaux des CRC. L’association entre le stade (stade II+ ou stade I) et l’appartenance ou non aux PN a été modélisée par régression logistique; pour les femmes des PN, nous avons examiné l’association entre les facteurs de risque et le stade.


Les femmes des PN (66%) ont été diagnostiquées à un stade plus tardif significativement plus souvent que les femmes non-PN (56%). Les femmes des PN ayant un cancer non dépisté (RC 5,03, IC 95% 2,48–10,21) et celles qui faisaient de l’embonpoint ou qui étaient obèses (RC 2,98, IC 95% 1,27–6,98 et RC 4,46, IC 95% 1,95–10,21, respectivement) étaient de manière significative plus susceptibles de recevoir un diagnostic à un stade plus avancé. La présence d’une comorbidité réduisait la probabilité d’un diagnostic tardif (RC 0,51, IC 95% 0,27–0,96) chez les femmes des PN.


Cette étude montre que les femmes des PN, en particulier celles qui ne font pas appel au système de santé, auraient besoin de participer à des programmes de dépistage du cancer du sein qui visent à détecter ces cancers plus tôt pour en améliorer le pronostic. Le système de soins en cancérologie de l’Ontario devrait donc mieux cibler cette population en améliorant la sensibilisation et l’accès au dépistage.


tumeurs du sein diagnostic facteurs de risque population indigène Ontario 


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Copyright information

© The Canadian Public Health Association 2010

Authors and Affiliations

  • Amanda J. Sheppard
    • 1
    • 2
    Email author
  • Anna M. Chiarelli
    • 1
    • 2
    • 3
  • Loraine D. Marrett
    • 1
    • 2
    • 3
  • Lucia Mirea
    • 2
    • 3
  • E. Diane Nishri
    • 2
  • Maureen E. Trudeau
    • 4
  • the Aboriginal Breast Cancer Study Group
  • Norman Boyd
    • 5
  • Paul Ferner
    • 6
  • Amanda Hey
    • 7
  • Caroline Lidstone-Jones
    • 8
  • Yolanda Madarnas
    • 9
  • Alison McMullen
    • 10
  • John Shaw
    • 11
  • Carol Rand
    • 12
  • Vincent Young
    • 13
  1. 1.Institute of Medical ScienceUniversity of TorontoTorontoCanada
  2. 2.Population Studies and SurveillanceCancer Care OntarioTorontoCanada
  3. 3.Dalla Lana School of Public HealthUniversity of TorontoTorontoCanada
  4. 4.Division of Medical Hematology-OncologyOdette Cancer CentreTorontoCanada
  5. 5.Princess Margaret HospitalCanada
  6. 6.London Regional Cancer CentreCanada
  7. 7.Hôpital régional de Sudbury Regional Hospital - Regional Cancer ProgramCanada
  8. 8.Cancer Care OntarioCanada
  9. 9.Cancer Centre of Southeastern OntarioCanada
  10. 10.Thunder Bay Regional Health Sciences CentreCanada
  11. 11.Windsor Regional Cancer ProgramCanada
  12. 12.Juravinski Cancer CentreCanada
  13. 13.Ottawa Hospital Cancer CentreCanada

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