Abstract
Objective
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.
Methods
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.
Results
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.
Conclusion
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.
Keywords: Breast neoplasms, diagnosis, risk factors, Indigenous population, Ontario
Résumé
Objectifs
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.
Méthode
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.
Résultats
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.
Conclusion
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.
Motsclés: tumeurs du sein, diagnostic, facteurs de risque, population indigène, Ontario
References
- 1.Canadian Cancer Society/National Cancer Institute of Canada. Canadian Cancer Statistics. 2009. [Google Scholar]
- 2.Marrett LD, Chaudhry M. Cancer incidence and mortality in Ontario First Nations, 1968–1991 (Canada) Cancer Causes Control. 2003;14(3):259–68. doi: 10.1023/A:1023632518568. [DOI] [PubMed] [Google Scholar]
- 3.Health Canada. A Statistical Profile on the Health of First Nations in Canada. First Nations and Inuit Health Branch. 2003. [Google Scholar]
- 4.Mahoney MC, Michalek AM. A meta-analysis of cancer incidence in United States and Canadian native populations. Int J Epidemiol. 1991;20(2):323–27. doi: 10.1093/ije/20.2.323. [DOI] [PubMed] [Google Scholar]
- 5.Rosenberg T, Martel S. Cancer trends from 1972–1991 for Registered Indians living on Manitoba Reserves. Int J Circumpolar Health. 1998;57(Suppl1):391–98. [PubMed] [Google Scholar]
- 6.Condon JR, Barnes T, Armstrong BK, Selva-Nayagam S, Elwood JM. Stage at diagnosis and cancer survival for Indigenous Australians in the Northern Territory. Med J Aust. 2005;182(6):277–80. doi: 10.5694/j.1326-5377.2005.tb06700.x. [DOI] [PubMed] [Google Scholar]
- 7.Samet JM, Key CR, Hunt WC, Goodwin JS. Survival of American Indian and Hispanic cancer patients in New Mexico and Arizona, 1969–82. J Natl Cancer Inst. 1987;79(3):457–63. [PubMed] [Google Scholar]
- 8.Dennis TD. Cancer stage at diagnosis, treatment, and survival among American Indians and non-American Indians in Montana. Cancer. 2000;89(1):181–86. doi: 10.1002/1097-0142(20000701)89:1<181::AID-CNCR24>3.0.CO;2-H. [DOI] [PubMed] [Google Scholar]
- 9.Tillman L, Myers S, Pockaj B, Perry C, Bay RC, Al-kasspooles M. Breast cancer in Native American women treated at an urban-based Indian health referral center 1982–2003. Am J Surg. 2005;190(6):895–902. doi: 10.1016/j.amjsurg.2005.08.017. [DOI] [PubMed] [Google Scholar]
- 10.Wampler NS, Lash TL, Silliman RA, Heeren TC. Breast cancer survival of American Indian/Alaska Native women, 1973–1996. Soz Praventivmed. 2005;50(4):230–37. doi: 10.1007/s00038-004-4020-6. [DOI] [PubMed] [Google Scholar]
- 11.Jeffreys M, Stevanovic V, Tobias M, Lewis C, Ellison-Loschmann L, Pearce N, et al. Ethnic inequalities in cancer survival in New Zealand: Linkage study. Am J Public Health. 2005;95(5):834–37. doi: 10.2105/AJPH.2004.053678. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Maskarinec G, Pagano IS, Yamashiro G, Issell BF. Influences of ethnicity, treatment, and comorbidity on breast cancer survival in Hawaii. J Clin Epidemiol. 2003;56(7):678–85. doi: 10.1016/S0895-4356(03)00079-9. [DOI] [PubMed] [Google Scholar]
- 13.Sugarman JR, Dennis LK, White E. Cancer survival among American Indians in western Washington State (United States) Cancer Causes Control. 1994;5(5):440–48. doi: 10.1007/BF01694758. [DOI] [PubMed] [Google Scholar]
- 14.Frost F, Tollestrup K, Hunt WC, Gilliland F, Key CR, Urbina CE. Breast cancer survival among New Mexico Hispanic, American Indian, and non-Hispanic white women (1973–1992) Cancer Epidemiol Biomarkers Prev. 1996;5(11):861–66. [PubMed] [Google Scholar]
- 15.Valery PC, Coory M, Stirling J, Green AC. Cancer diagnosis, treatment, and survival in Indigenous and non-Indigenous Australians: A matched cohort study. Lancet. 2006;367(9525):1842–48. doi: 10.1016/S0140-6736(06)68806-5. [DOI] [PubMed] [Google Scholar]
- 16.Rosenberg J, Chia YL, Plevritis S. The effect of age, race, tumor size, tumor grade, and disease stage on invasive ductal breast cancer survival in the U.S. SEER database. Breast Cancer Res Treat. 2005;89(1):47–54. doi: 10.1007/s10549-004-1470-1. [DOI] [PubMed] [Google Scholar]
- 17.McBride R, Hershman D, Tsai WY, Jacobson JS, Grann V, Neugut AI. Within-stage racial differences in tumor size and number of positive lymph nodes in women with breast cancer. Cancer. 2007;110(6):1201–8. doi: 10.1002/cncr.22884. [DOI] [PubMed] [Google Scholar]
- 18.Begg CB, Zhang ZF. Statistical analysis of molecular epidemiology studies employing case-series. Cancer Epidemiol Biomarkers Prev. 1994;3(2):173–75. [PubMed] [Google Scholar]
- 19.American Joint Committee on Cancer. Cancer Staging Manual. New York. 2002. [Google Scholar]
- 20.Groome PA, Schulze KM, Keller S, Mackillop WJ. Demographic differences between cancer survivors and those who die quickly of their disease. Clin Oncol (R Coll Radiol) 2008;20(8):647–56. doi: 10.1016/j.clon.2008.05.006. [DOI] [PubMed] [Google Scholar]
- 21.National Institutes of Health: Clinical Guidelines on the Identification, Evaluation,Treatment of OverweightObesity in Adults—The Evidence Report. National Institutes of Health. Obes Res. 1998;6(Suppl2):51S–209S. [PubMed] [Google Scholar]
- 22.Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation. J Chronic Dis. 1987;40(5):373–83. doi: 10.1016/0021-9681(87)90171-8. [DOI] [PubMed] [Google Scholar]
- 23.Sagiv SK, Gaudet MM, Eng SM, Abrahamson PE, Shantakumar S, Teitelbaum SL, et al. Active and passive cigarette smoke and breast cancer survival. Ann Epidemiol. 2007;17(5):385–93. doi: 10.1016/j.annepidem.2006.11.004. [DOI] [PubMed] [Google Scholar]
- 24.Condon JR, Cunningham J, Barnes T, Armstrong BK, Selva-Nayagam S. Cancer diagnosis and treatment in the Northern Territory: Assessing health service performance for indigenous Australians. Intern Med J. 2006;36(8):498–505. doi: 10.1111/j.1445-5994.2006.01134.x. [DOI] [PubMed] [Google Scholar]
- 25.Jacobellis J, Cutter G. Mammography screening and differences in stage of disease by race/ethnicity. Am J Public Health. 2002;92(7):1144–50. doi: 10.2105/AJPH.92.7.1144. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Gracey M, King M. Indigenous health part 1: Determinants and disease patterns. Lancet. 2009;374(9683):65–75. doi: 10.1016/S0140-6736(09)60914-4. [DOI] [PubMed] [Google Scholar]
- 27.Fleming ST, Pursley HG, Newman B, Pavlov D, Chen K. Comorbidity as a predictor of stage of illness for patients with breast cancer. Med Care. 2005;43(2):132–40. doi: 10.1097/00005650-200502000-00006. [DOI] [PubMed] [Google Scholar]
- 28.Minore B, Boone M, Katt M, Kinch P, Birch S, Mushquash C. The effects of nursing turnover on continuity of care in isolated First Nation communities. Can J Nurs Res. 2005;37(1):86–100. [PubMed] [Google Scholar]
- 29.Minore B, Boone M, Katt M, Kinch P, Cromarty H. Int J Circumpolar Health. 2004. How clients choices influence cancer care in northern Aboriginal communities. [DOI] [PubMed] [Google Scholar]
- 30.Friedman DB, Hoffman-Goetz L. Assessment of cultural sensitivity of cancer information in ethnic print media. J Health Commun. 2006;11(4):425–47. doi: 10.1080/10810730600671920. [DOI] [PubMed] [Google Scholar]