Primary liver cancer incidence among American Indians and Alaska Natives, US, 1999-2004.
BACKGROUND
American Indians and Alaska Natives (AI/AN) experience higher morbidity and mortality from primary liver cancer than other United States (US) populations, but racial misclassification in medical records results in underestimates of disease burden.


METHODS
To reduce misclassification, National Program of Cancer Registries and Surveillance, Epidemiology, and End Results data were linked with Indian Health Service (IHS) enrollment records to compare primary liver cancer incidence and stage at diagnosis between AI/AN and non-Hispanic whites (NHW) living within the regionalized IHS Contract Health Service Delivery Area counties. Incidence rates are expressed per 100,000 persons and age-adjusted by 19 age groups to the 2000 US standard population.


RESULTS
Overall, AI/AN have a higher proportion of hepatocellular carcinoma compared with NHW, 77.8% versus 66.7%. Liver cancer incidence rates among AI/AN males and females were higher than those among NHW males and females for all regions except for the East. Among males, rates ranged from 7.3 (95% confidence interval [CI], 3.8-12.6) in the East to 17.2 (95% CI, 10.4-26.3) in Alaska. Among females, rates ranged from 3.8 (95% CI, 1.4-8.2) in the East to 6.9 (95% CI, 3.6-11.6) in Alaska. The AI/AN rates for all regions were consistently higher than the NHW rates at every age. An increasing trend among AI/AN was suggested but did not achieve statistical significance.


CONCLUSIONS
Reducing racial misclassification revealed higher disparities in primary liver cancer incidence between NHW and AI/AN populations than previously reported. Further description of the reasons for regional differences in this disparity is needed, as are programs to reduce risk factors and to diagnose primary liver cancer at earlier, more treatable stages.
Jim
Melissa A
MA
Division of Cancer Prevention and Control, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. melissa.jim@ihs.gov
Perdue
David G
DG
Richardson
Lisa C
LC
Espey
David K
DK
Redd
John T
JT
Martin
Howard J
HJ
Kwong
Sandy L
SL
Kelly
Janet J
JJ
Henderson
Jeffrey A
JA
Ahmed
Faruque
F
D000230:Adenocarcinoma / Q000208:ethnology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000413:Alaska / Q000453:epidemiology; 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*; D008113:Liver Neoplasms / Q000208:ethnology*; D008875:Middle Aged; D011159:Population Surveillance; D044469:Racial Groups / Q000706:statistics & numerical data; D012042:Registries; D014481:United States / Q000453:epidemiology