Breast cancer incidence among American Indian and Alaska Native women: US, 1999-2004.
BACKGROUND
Breast cancer is a leading cause of cancer morbidity and mortality among American Indian and Alaska Native (AI/AN) women. Although published studies have suggested that breast cancer rates among AI/AN women are lower than those among other racial and ethnic populations, accurate determinations of the breast cancer burden have been hampered by misclassification of AI/AN race.


METHODS
Cancer incidence data from the National Program of Cancer Registries and the Surveillance, Epidemiology, and End Results Program were combined to estimate age-adjusted rates for the diagnosis years 1999 through 2004. Several steps were taken to reduce the misclassification of AI/AN race: linking cases to Indian Health Service (IHS) patient services database, restricting analyses to Contract Health Service Delivery Area counties, and stratifying results by IHS region.


RESULTS
Breast cancer incidence rates among AI/AN women varied nearly 3-fold across IHS regions. The highest rates were in Alaska (134.8) and the Plains (Northern, 115.9; Southern, 115.7), and the lowest rates were in the Southwest (50.8). The rate in Alaska was similar to the rate among non-Hispanic white (NHW) women in Alaska. Overall, AI/AN women had lower rates of breast cancer than NHW women, but AI/AN women were more likely to be diagnosed with late-stage disease.


CONCLUSIONS
To the authors' knowledge, this report provides the most comprehensive breast cancer incidence data for AI/AN women to date. The wide regional variation indicates an important need for etiologic and health services research, and the large percentage of AI/AN women with late-stage disease demands innovative approaches for increasing access to screening.
Wingo
Phyllis A
PA
National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
King
Jessica
J
Swan
Judith
J
Coughlin
Steven S
SS
Kaur
Judith S
JS
Erb-Alvarez
Julie A
JA
Jackson-Thompson
Jeannette
J
Arambula Solomon
Teshia G
TG
D000230:Adenocarcinoma / Q000208:ethnology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000413:Alaska / Q000453:epidemiology; D001943:Breast Neoplasms / Q000208:ethnology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007198:Indians, North American / Q000706:statistics & numerical data*; D007223:Infant; D007231:Infant, Newborn; D004930:Inuit / Q000706:statistics & numerical data*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011159:Population Surveillance; D044469:Racial Groups / Q000706:statistics & numerical data; D012042:Registries; D014481:United States / Q000453:epidemiology