Janet J. Kelly

Cancer among American Indians and Alaska Natives in the United States, 1999–2004

Cancer incidence rates vary among American Indian and Alaska Native (AI/AN) populations and often differ from rates among non‐Hispanic whites (NHWs). However, the misclassification of race for AI/AN cancer cases in central cancer registries may have led to underestimates of the AI/AN cancer burden in previous reports.

Differences in Cancer Incidence among Indians in Alaska and New Mexico and U.S. Whites, 1993-2002

Cancer incidence for American Indians and Alaska Natives is typically reported as a single rate for all U.S. indigenous populations combined. Previously reported combined rates suggest that American Indians and Alaska Natives have lower cancer incidence rates compared with the U.S. population. Alaska Native people comprise three major ethnic groups: Eskimo, Indian, and Aleut people. We examined cancer incidence from only Alaska Indians and compared incidence rates with an American Indian population living in New Mexico. These data indicate striking differences in cancer patterns between two American Indian populations. Cancer data for the years 1993 to 2002 for American Indians of New Mexico and U.S. Whites are from the National Cancer Institute Surveillance, Epidemiology, and End Results Program Public-use data set. Data for Alaska Indians are from the Alaska Native Tumor Registry, which is also a Surveillance Epidemiology and End Results Program participant. Overall, cancer incidence rates for all sites combined in New Mexico Indian men and women were lower than U.S. White rates, whereas Alaska Indian men and women exceeded U.S. rates. In comparing Alaska and New Mexico Indians, we observed a 2.5-fold higher incidence of cancer among Alaska Indians. The largest differences between the two Indian populations were noted primarily in cancers associated with tobacco use, including cancers of the oral cavity/pharynx, esophagus (only in men), colon and rectum, pancreas, larynx (men), lung, prostate, and urinary bladder (men). Lung cancer rates in Alaska Indian men and women were 7 and 10 times those of New Mexico Indian men and women. (Cancer Epidemiol Biomarkers Prev 2006;15(8):1515–9)

Cancers of the breast, uterus, ovary and cervix among Alaska Native women, 1974-2003

Objectives. Alaska Native (AN) women have exhibited some of the highest incidence rates of cancer overall, and different patterns of site-specific incidence compared to other U.S. populations. This study compares incidence rates between AN and U.S. white women (USW) for cancers of the breast, uterus, ovary and cervix, and examines effects of time period and birth cohort as determinants of incidence trends among AN women. Study design. Observational, population-based study. Methods. Cancer incidence data from the Alaska Native Tumor Registry and SEERStat, 1974– 2003. Age-adjusted World Standard Population rates were calculated for a current 5-year period and over time (30 years), and compared to other populations using rate ratios with 95% confidence intervals. Log-linear regression models used to assess impact on trend of age, time period and birth cohort. Results. Compared to U.S. white women, current cancer rates among AN women are not significantly different for cancer of the breast and cervix, and significantly lower for cancers of the ovary and uterus. Trends over time over a 30-year time period also differ for these cancer sites. There were significant increases in breast and uterine cancer, and in contrast, a marked decline in cervical cancer. There was no significant change for cancer of the ovary. Changes appear to be due largely to period, not birth cohort effects. Conclusions. Increases in breast cancer may be due to a combination of modifiable behaviours; increased BMI and a shift to a non-traditional diet. Increases in uterine cancer could be associated with increased BMI and diabetes. Cervical cancer rates have declined to USW levels. The marked decline is likely due to enhanced screening and control efforts within the Alaska Native Tribal Health System (formerly Alaska Area USPHS, Indian Health Service utilizing resources available from the Centers for Disease Control tribal and state Breast and Cervical Cancer Early Detection Programs).

Cancers of the Urinary Tract Among American Indians and Alaska Natives in the United States, 1999–2004

Assessment of the kidney parenchyma (“kidney”) and urinary bladder (“bladder”) cancer burden among American Indians and Alaska Natives (AI/AN) has been limited. Using a database with improved classification for AI/AN, the authors described patterns of these 2 cancers among AI/AN and non‐Hispanic whites (NHW) in the United States.

Primary liver cancer incidence among American Indians and Alaska Natives, US, 1999-2004

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.

Incidence of cancers of the oral cavity and pharynx among American Indians and Alaska Natives, 1999–2004†‡§

Previous studies identified disparities in incidence rates of cancers of the oral cavity and pharynx between American Indians/Alaska Natives (AI/AN) and non‐Hispanic whites (NHW) and differences between various AI/AN populations. Reporting among AI/AN has been hampered by: 1) heterogeneity among various anatomic sites of oral cavity and pharyngeal cancers obscuring unique patterns of individual anatomic sites; 2) race misclassification and underreporting of AI/AN; and 3) sparseness of data needed to identify regional variations.

Cancer among circumpolar populations: an emerging public health concern

Objectives To determine and compare the incidence of cancer among the 8 Arctic States and their northern regions, with special focus on 3 cross-national indigenous groups – Inuit, Athabaskan Indians and Sami. Methods Data were extracted from national and regional statistical agencies and cancer registries, with direct age-standardization of rates to the world standard population. For comparison, the “world average” rates as reported in the GLOBOCAN database were used. Findings Age-standardized incidence rates by cancer sites were computed for the 8 Arctic States and 20 of their northern regions, averaged over the decade 2000–2009. Cancer of the lung and colon/rectum in both sexes are the commonest in most populations. We combined the Inuit from Alaska, Northwest Territories, Nunavut and Greenland into a “Circumpolar Inuit” group and tracked cancer trends over four 5-year periods from 1989 to 2008. There has been marked increase in lung, colorectal and female breast cancers, while cervical cancer has declined. Compared to the GLOBOCAN world average, Inuit are at extreme high risk for lung and colorectal cancer, and also certain rare cancers such as nasopharyngeal cancer. Athabaskans (from Alaska and Northwest Territories) share some similarities with the Inuit but they are at higher risk for prostate and breast cancer relative to the world average. Among the Sami, published data from 3 cohorts in Norway, Sweden and Finland show generally lower risk of cancer than non-Sami. Conclusions Cancer among certain indigenous people in the Arctic is an increasing public health concern, especially lung and colorectal cancer.

Prostate cancer in Alaska Native men, 1969-2003

Objectives. The incidence of prostate cancer differs significantly between US race groups. In prior reviews of cancer in Alaska Natives, the incidence of prostate cancer has been observed to occur at a low rate compared to US Whites and Blacks. However, a detailed report of prostate cancer in this population has not been previously published. Study Design. Incidence of prostate cancer in Alaska Native men was determined for the time period 1969–2003 using data from the Alaska Native Tumor Registry. The registry is a population-based registry which participates in the National Cancer Institute Surveillance, Epidemiology and End Results Program, and has collected cancer information on Alaska Natives since 1969. Methods. Incidence rates were calculated for all Alaska Natives and for each of the three major ethnic groups (Aleut, Eskimo, Indian). Comparisons of incidence rates between Alaska Natives and US Whites were performed using odds ratios. Temporal changes were identified by a Chi square analysis for trend. Results. During the 35-year period of review, 332 Alaska Native men were diagnosed with prostate cancer. The age-adjusted incidence rate of 69.5 per 100 000 in Alaska Native men during 1994–2003 was significantly higher than the rate of 45.5 per 100 000 for the earlier period 1969-1983. The US White rate for 1994-2002 of 169.5 per 100 000 was significantly higher than the rate for Alaska Native men for 1994-2003. Results of comparisons between Alaska Native ethnic groups for 1969-2003 showed that prostate cancer was highest in Indians and Aleuts and lowest among Eskimos. Conclusions. Compared to the US White population, the incidence of prostate cancer in Alaska Native men is significantly lower. Prostate cancer rates among Alaska Native ethnic groups differ. The reason for these differences remains undetermined.

Pap prevalence and cervical cancer prevention among Alaska Native women.

The goals of the Alaska Native Womens Health Project (WHP) were to determine the following: (1) Pap prevalence based on chart review before and during an intervention period; (2) the level of understanding of cancer and cancer screening services with emphasis on cervical cancer; (3) use and satisfaction with current health maintenance services; and (4) improvement in knowledge and cancer screening rates following intervention. A random sample of 481 Alaska Native (Eskimo, Aleut, Indian) women living in Anchorage were interviewed face to face about their understanding of cancer risk factors (tobacco use, sexually transmitted diseases (STDs), reproductive issues), cancer screening examinations (Pap test, breast self-examination (BSE), breast exam by a provider, mammography), and their attitudes about health care and health care services. Sixty-two percent of control women were documented to have had at least one Pap test within the 3-year period prior to the beginning of the study; however, only 9% were documented to have had annual Pap screening. The intervention included distribution of educational materials, counseling on any womans health issue, special evening clinics, and reminders (mail/phone call) of scheduled Pap appointments.

Helicobacter pylori infection and markers of gastric cancer risk in Alaska Native persons: A retrospective case-control study

BACKGROUND Alaska Native persons experience gastric cancer incidence and mortality rates that are three to four times higher than in the general United States population. OBJECTIVE To evaluate pepsinogen I, pepsinogen I/II ratio, anti-Helicobacter pylori and cytotoxin-associated gene A (CagA) antibody levels, and blood group for their associations with gastric cancer development in Alaska Native people. METHODS The present analysis was a retrospective case-control study that matched gastric cancers reported to the Alaska Native Tumor Registry from 1969 to 2008 to three controls on known demographic risk factors for H pylori infection, using sera from the Alaska Area Specimen Bank. Conditional logistic regression evaluated associations between serum markers and gastric cancer. RESULTS A total of 122 gastric cancer cases were included, with sera predating cancer diagnosis (mean = 13 years) and 346 matched controls. One hundred twelve cases (91.8%) and 285 controls (82.4%) had evidence of previous or ongoing H pylori infection as measured by anti-H pylori antibody levels. Gastric cancer cases had a 2.63-fold increased odds of having positive anti-H pylori antibodies compared with their matched controls (P=0.01). In a multivariate model, noncardia gastric cancer (n=94) was associated with anti-H pylori antibodies (adjusted OR 3.92; P=0.004) and low pepsinogen I level (adjusted OR 6.04; P=0.04). No association between gastric cancer and blood group, anti-CagA antibodies or pepsinogen I/II ratio was found. CONCLUSION Alaska Native people with gastric cancer had increased odds of previous H pylori infection. Low pepsinogen I level may function as a precancer marker for noncardia cancer.