Cancer in American Indian and Alaska Native young adults (ages 20-44 years): US, 1999-2004

Assessment of Racial Misclassification Among American Indian and Alaska Native Identity in Cancer Surveillance Data in the United States and Considerations for Oral Health: A Systematic Review

Introduction

Misclassification of American Indian and Alaska Native (AI/AN) peoples exists across various databases in research and clinical practice. Oral health is associated with cancer incidence and survival; however, misclassification adds another layer of complexity to understanding the impact of poor oral health. The objective of this literature review was to systematically evaluate and analyze publications focused on racial misclassification of AI/AN racial identities among cancer surveillance data.

Methods

The PRISMA Statement and the CONSIDER Statement were used for this systematic literature review. Studies involving the racial misclassification of AI/AN identity among cancer surveillance data were screened for eligibility. Data were analyzed in terms of the discussion of racial misclassification, methods to reduce this error, and the reporting of research involving Indigenous peoples.

Results

A total of 66 articles were included with publication years ranging from 1972 to 2022. A total of 55 (83%) of the 66 articles discussed racial misclassification. The most common method of addressing racial misclassification among these articles was linkage with the Indian Health Service or tribal clinic records (45 articles or 82%). The average number of CONSIDER checklist domains was three, with a range of zero to eight domains included. The domain most often identified was Prioritization (60), followed by Governance (47), Methodologies (31), Dissemination (27), Relationships (22), Participation (9), Capacity (9), and Analysis and Findings (8).

Conclusion

To ensure equitable representation of AI/AN communities, and thwart further oppression of minorities, specifically AI/AN peoples, is through accurate data collection and reporting processes.

Misracialization of Indigenous people in population health and mortality studies: a scoping review to establish promising practices

Indigenous people are often misracialized as other racial or ethnic identities in population health research. This misclassification leads to underestimation of Indigenous-specific mortality and health metrics, and subsequently, inadequate resource allocation. In recognition of this problem, investigators around the world have devised analytic methods to address racial misclassification of Indigenous people. We carried out a scoping review based on searches in PubMed, Web of Science, and the Native Health Database for empirical studies published after 2000 that include Indigenous-specific estimates of health or mortality and that take analytic steps to rectify racial misclassification of Indigenous people. We then considered the weaknesses and strengths of implemented analytic approaches, with a focus on methods used in the US context. To do this, we extracted information from 97 articles and compared the analytic approaches used. The most common approach to address Indigenous misclassification is to use data linkage; other methods include geographic restriction to areas where misclassification is less common, exclusion of some subgroups, imputation, aggregation, and electronic health record abstraction. We identified 4 primary limitations of these approaches: (1) combining data sources that use inconsistent processes and/or sources of race and ethnicity information; (2) conflating race, ethnicity, and nationality; (3) applying insufficient algorithms to bridge, impute, or link race and ethnicity information; and (4) assuming the hyperlocality of Indigenous people. Although there is no perfect solution to the issue of Indigenous misclassification in population-based studies, a review of this literature provided information on promising practices to consider.

Incidence of selected cancers in Non-Hispanic American Indian and Alaska Native adolescent and young adult populations, 1999-2019

PURPOSE

Studies have highlighted geographic variation in cancer incidence rates among American Indian and Alaska Native (AI/AN) populations. This is the first study to comprehensively evaluate incidence rates and trends among non-Hispanic AI/AN (NH-AI/AN) adolescents and young adults (AYAs) ages 15-39 years.

METHODS

Using the United States Cancer Statistics AI/AN Incidence Analytic Database, we identified all malignant cancer cases for NH-AI/AN AYA populations for the years 1999-2019. We calculated age-adjusted incidence rates (per 100,000) for NH-AI/AN populations overall, by region, and by age group. We calculated the total percent change in the incidence of leading AYA cancers between 1999 and 2019, and trends by region and cancer type using Joinpoint analysis.

RESULTS

Testicular (13.6) and breast (19.0) cancers had the highest incidence of all AYA cancers in NH-AI/AN males and females, respectively. Overall AYA cancer rates increased by 1.4% in NH-AI/AN males and 1.8% in NH-AI/AN females annually between 1999 and 2019. Increases were observed by age group and geographic region.

CONCLUSIONS

This study describes regional differences in incidence rates of AYA cancers among NH-AI/AN populations. This data can help inform resource and cancer control priorities and strategies to reduce cancer risk and enhance access to quality diagnostic and treatment services for this population.

Disparities in the impact of the AJCC 8th edition staging system on differentiated thyroid cancer outcomes

BACKGROUND

The impact of AJCC8 among self-reported racial/ethnic groups on differentiated thyroid cancer (DTC) outcomes is unknown.

METHODS

Multivariate-regression evaluated the association between AJCC7 to AJCC8 stage change and race/ethnicity in patients with DTC in the NCDB. Cox-proportional-regression evaluated whether AJCC7 to AJCC8 stage change affects overall survival (OS) differently based on reported race/ethnicity.

RESULTS

After adjusting for confounders, Hispanics and Asian-Pacific-Islanders (APIs) were 27% and 12% less likely to be down-staged compared to white-non-Hispanics (WNHs) (p < 0.001); black-non-Hispanics (BNHs) had no significant down-staging difference. Down-staged patients had an increased risk of death compared to patients with unchanged staging, regardless of race/ethnicity. However, based on two-way interaction, the magnitude of this negative change on survival from down-staging was only different between WNHs (HR = 2.64) and BNHs (HR = 1.77), (p = 0.04).

CONCLUSIONS

Outcome disparities persist among self-reported racial/ethnic groups with AJCC8. Down-staged patients across all racial/ethnic groups had decreased survival compared to those with unchanged stage, with the least impact in BNHs.

Gynecologic cancer incidence and mortality among American Indian/Alaska Native women in the Pacific Northwest, 1996-2016

OBJECTIVES

Compare the incidence and mortality of gynecologic cancers among American Indian/Alaska Native (AI/AN) women to the Non-Hispanic White (NHW) population in the Pacific Northwest.

METHODS

Age-adjusted cancer incidence (1996-2016) and mortality (2006-2016) rates were calculated from population-based state cancer registry and death certificate data obtained from Washington, Oregon, and Idaho, and corrected for AI/AN misclassification. Incidence and mortality rate ratios (RR) were calculated to compare AI/AN and NHW women with gynecologic cancers.

RESULTS

Across all gynecologic cancer sites, AI/AN women were diagnosed at a younger age compared to NHW women. AI/AN women had a higher incidence of cervical cancer compared to NHW women with a RR of 1.53 (95% CI: 1.34, 1.75). For all age groups, AI/AN women had a higher incidence of cervical cancer and the disparity was greatest in the 50-64 age group with a RR of 1.76 (95% CI: 1.36, 2.30). Cervical cancer mortality was greater among AI/AN women, with an all-ages RR of 1.79 (95% CI: 1.30, 2.46); the disparity was greatest in the 50-64 age group (RR: 2.88, 95% CI: 1.89, 4.38). For uterine cancer, AI/AN women had similar incidence rates as NHW women but higher mortality rates (RR: 1.35, 95% CI: 1.03-1.75). Incidence and mortality for ovarian cancer were similar between groups.

CONCLUSION

Our analysis of gynecologic cancers among AI/AN in the PNW found significant disparities relative to NHW women in cervical cancer incidence and mortality. These disparities persist despite advances in prevention strategies.

Testicular Cancer Incidence and Mortality Within Rural and Urban Regions

Purpose: Testicular cancer (TCa) is among the most common cancers within adolescent and young adult (AYA) male populations. However, information is limited to variations in incidence and mortality outside of racial/ethnic subgroups. Rural regions historically have a greater overall cancer incidence than urban regions, although some key differences exist regarding site. TCa-specific incidence and mortality disparities are not commonly reported in this context. This study aims to help fill that gap by providing discovery evidence if there is an association between US rural/urban regions and TCa incidence and mortality. Methods: Secondary analysis of Surveillance, Epidemiology, and End Results incidence and mortality data were employed to determine if rural/urban TCa incidence and mortality disparities exist among U.S. males. Results: There was a 2.6% increased rate of TCa in U.S. urban as compared with rural geographic regions from 2011 to 2015. When geographic region is disaggregated, rural regions see higher rates than urban. When factoring in race/ethnicity, White/Caucasians and Hispanics had statistically higher urban rates whereas American Indian/Alaskan Natives and Asian/Pacific Islander groups had statistically higher rural rates. Conclusion: Geographic regional TCa variation research is virtually nonexistent for U.S. males, specifically AYAs of color. Determining preliminary trends in rural and urban regions can assist in the creation of more targeted services, particularly among underserved and vulnerable populations that have tenuous access to health care, to reduce disparate health outcomes. Exploring geographic differences in TCa incidence and mortality can have implications within service industry, health care accessibility, and public health justice areas of research and outreach.

Racial/Ethnic Patterns of Young-Onset Noncardia Gastric Cancer

Increasing noncardia gastric cancer incidence rates among individuals age younger than 50 years have gained much attention, particularly as causes remain unknown. Using population-based NIH/NCI's Surveillance, Epidemiology, and End Results (SEER) program data from 2007 to 2015, multivariable logistic regression was used to quantify associations between race/ethnicity and clinicodemographic features among young-onset noncardia gastric cancer patients. A total of 2,872 individuals ages 20 to 49 years were diagnosed with primary noncardia gastric cancer. Age at diagnosis, insurance status, anatomic subsite, American Joint Committee on Cancer (AJCC) clinical stage, histologic type, tumor grade, surgery, and county-level smoking prevalence differed by race/ethnicity (all P ≤ 0.003). Compared with non-Hispanic whites, Hispanics were more likely to be diagnosed at younger ages [odds ratio (OR) = 0.97; 95% confidence intervals (CI), 0.95-0.99], on Medicaid/uninsured (OR = 3.83; 95% CI, 2.89-5.08), diagnosed with higher grade tumors (OR = 1.93; 95% CI, 1.32-2.84), and less likely to undergo surgery (OR = 0.62; 95% CI, 0.44-0.88) or to reside in counties with higher smoking prevalence (OR = 0.15; 95% CI, 0.11-0.21) after adjustment for sex, subsite, and histologic type. Asian/Pacific Islanders were more likely to be female (OR = 1.40; 95% CI, 1.04-1.88), and less likely to be diagnosed with metastatic disease (OR = 0.59; 95% CI, 0.37-0.95) or to reside in counties with higher smoking prevalence (OR = 0.13; 95% CI, 0.08-0.19). Approximately two in every five patients with young-onset noncardia gastric cancer are Hispanic. Further investigation into the molecular heterogeneity of young-onset noncardia gastric cancers by race/ethnicity to understand etiologies underlying this rising disease epidemic is warranted. This population-based cohort study sheds light that biological and environmental factors may partly underlie race/ethnicity-related differences in young-onset noncardia gastric cancer susceptibility and outcomes.

Breast cancer in adolescents and young adults

Breast cancer is the most common cancer of adolescents and young adult (AYA) women aged 15 to 39 years, accounting for 5.6% of all invasive breast cancer in women. In comparison with older women, AYAs are more likely to have familial cancer predisposition genes, larger breast tumors, unfavorable biological characteristics, distant metastatic disease at diagnosis, and adverse outcome. Endocrine therapy and some chemotherapy recommendations differ between young and older women. AYAs require coordinated multidisciplinary care, treatment regimens that minimize late effects such as premature menopause and osteoporosis, and proactive management of psychological and sexual health during and after cancer treatment.

American Indian Knowledge, Attitudes, and Beliefs About Smokeless Tobacco: A Comparison of Two Focus Group Studies

Though smokeless tobacco (SLT) use has decreased in many communities, concern for American Indian (AI) SLT use remains, as this population continues to be disproportionally affected by SLT-related diseases. Tobacco has cultural significance to many AI tribes, therefore tobacco cessation messages portraying tobacco as entirely negative may be ineffective. As a part of our formative research for an SLT cessation intervention, we sought to gain a better understanding of the knowledge, attitudes, and beliefs about SLT among AI community members. We describe two independent focus group studies conducted in Montana (ten focus groups, 54 participants) and Kansas (six focus groups, 27 participants). Predominant themes emerged from three major topic areas (SLT use, program development, and recreational SLT use) during the discussions from both studies. The formative approach and data from these studies will allow us to more appropriately address SLT-related health disparities across multiple AI communities.

Kidney cancer incidence and mortality among American Indians and Alaska Natives in the United States, 1990-2009

OBJECTIVES

We describe rates and trends in kidney cancer incidence and mortality and identify disparities between American Indian/Alaska Native (AI/AN) and White populations.

METHODS

To improve identification of AI/AN race, incidence and mortality data were linked with Indian Health Service (IHS) patient records. Analysis focused on residents of IHS Contract Health Service Delivery Area counties; Hispanics were excluded. We calculated age-adjusted kidney cancer incidence (2001-2009) and death rates (1990-2009) by sex, age, and IHS region.

RESULTS

AI/AN persons have a 1.6 times higher kidney cancer incidence and a 1.9 times higher kidney cancer death rate than Whites. Despite a significant decline in kidney cancer death rates for Whites (annual percentage change [APC] = -0.3; 95% confidence interval [CI] = -0.5, 0.0), death rates for AI/AN persons remained stable (APC = 0.4; 95% CI = -0.7, 1.5). Kidney cancer incidence rates rose more rapidly for AI/AN persons (APC = 3.5; 95% CI = 1.2, 5.8) than for Whites (APC = 2.1; 95% CI = 1.4, 2.8).

CONCLUSIONS

AI/AN individuals have greater risk of developing and dying of kidney cancers. Incidence rates have increased faster in AI/AN populations than in Whites. Death rates have decreased slightly in Whites but remained stable in AI/AN populations. Racial disparities in kidney cancer are widening.

International variations in childhood cancer in indigenous populations: a systematic review

Although the cancer burden in indigenous children has been reported in some countries, up to now, no international comparison has been made. We therefore aimed to assess the available evidence of the burden of childhood cancer in indigenous populations. We did a systematic review of reports on cancer incidence, mortality, and survival in indigenous children worldwide. Our findings highlight the paucity of accessible information and advocate the pressing need for data by indigenous status in countries where population-based cancer registries are established. The true extent of disparities between the burden in the indigenous community needs to be measured so that targeted programmes for cancer control can be planned and implemented.

Breast cancer screening perceptions among American Indian women under age 40

Breast cancer mortality rates are the second leading cause of cancer death in American Indian (AI) women. AI breast cancer screening rates have been decreasing, and AI women have some of the lowest screening rates compared to other racial/ethnic groups. Our research team investigated breast cancer and breast cancer screening education prior to recommended age for screening. It is imperative to examine the perspectives of young AI women toward breast cancer screening to better understand screening perceptions among AI women. Following a community-based participatory research approach, we conducted five focus groups and four interviews with AI women aged 25-39 (N = 48) in Kansas and Missouri. Nine themes emerged from the focus groups and relate to topics such as the following: knowledge of breast cancer and breast cancer screening, barriers to screening and treatment, suggestions to improve access, and perceptions and use of health-care systems. Specifically, we found that AI women lacked knowledge of details about screenings and their risks for getting breast cancer, cost was cited as a primary barrier to screening, additional education was needed (particularly materials that were AI focused), breast health was generally not discussed with others, and more instruction was requested for techniques used to identify bodily changes or abnormalities. Understanding attitudes of AI women not of recommended screening age may provide an insight into low screening rates among AI women. Furthermore, the results may inform outreach strategies to improve current and future screening rates.

Do ethnic patterns in cryptorchidism reflect those found in testicular cancer?

PURPOSE

There are established variations in testicular cancer incidence between ethnic groups within countries. It is currently unclear whether the occurrence of cryptorchidism-a known risk factor for testicular cancer-follows similar patterns. In New Zealand Māori have unusually high rates of testicular cancer compared to individuals of European ancestry. We hypothesized that ethnic trends in the incidence of cryptorchidism would reflect those for testicular cancer in this setting.

MATERIALS AND METHODS

We followed 318,441 eligible male neonates born in New Zealand between 2000 and 2010 for the incidence of orchiopexy confirmed cryptorchidism and the incidence of known risk factors for cryptorchidism (low birth weight, short gestation, small size for gestational age) using routine maternity, hospitalization and mortality records. Logistic regression was used to calculate odds ratios for the presence of known risk factors for cryptorchidism by ethnic group. Poisson regression was used to calculate relative risk of cryptorchidism by ethnicity, adjusted for risk factors.

RESULTS

Ethnic patterns of cryptorchidism incidence in New Zealand closely mirrored those previously observed for testicular cancer. Māori had higher rates of cryptorchidism than all other ethnic groups (adjusted RR 1.2 [95% CI 1.11-1.3]), with Pacific (0.89 [0.8-0.99]) and Asian groups (0.68 [0.59-0.79]) having the lowest rates (European/other, referent).

CONCLUSIONS

Since the principal risk factors for cryptorchidism are present in utero, the results of the current study strengthen the likelihood that the ethnic patterning of testicular cancer is at least partly due to prenatal risk factors.

Health disparities in endocrine disorders: biological, clinical, and nonclinical factors--an Endocrine Society scientific statement

OBJECTIVE

The aim was to provide a scholarly review of the published literature on biological, clinical, and nonclinical contributors to race/ethnic and sex disparities in endocrine disorders and to identify current gaps in knowledge as a focus for future research needs. PARTICIPANTS IN DEVELOPMENT OF SCIENTIFIC STATEMENT: The Endocrine Society's Scientific Statement Task Force (SSTF) selected the leader of the statement development group (S.H.G.). She selected an eight-member writing group with expertise in endocrinology and health disparities, which was approved by the Society. All discussions regarding the scientific statement content occurred via teleconference or written correspondence. No funding was provided to any expert or peer reviewer, and all participants volunteered their time to prepare this Scientific Statement.

EVIDENCE

The primary sources of data on global disease prevalence are from the World Health Organization. A comprehensive literature search of PubMed identified U.S. population-based studies. Search strategies combining Medical Subject Headings terms and keyword terms and phrases defined two concepts: 1) racial, ethnic, and sex differences including specific populations; and 2) the specific endocrine disorder or condition. The search identified systematic reviews, meta-analyses, large cohort and population-based studies, and original studies focusing on the prevalence and determinants of disparities in endocrine disorders. consensus process: The writing group focused on population differences in the highly prevalent endocrine diseases of type 2 diabetes mellitus and related conditions (prediabetes and diabetic complications), gestational diabetes, metabolic syndrome with a focus on obesity and dyslipidemia, thyroid disorders, osteoporosis, and vitamin D deficiency. Authors reviewed and synthesized evidence in their areas of expertise. The final statement incorporated responses to several levels of review: 1) comments of the SSTF and the Advocacy and Public Outreach Core Committee; and 2) suggestions offered by the Council and members of The Endocrine Society.

CONCLUSIONS

Several themes emerged in the statement, including a need for basic science, population-based, translational and health services studies to explore underlying mechanisms contributing to endocrine health disparities. Compared to non-Hispanic whites, non-Hispanic blacks have worse outcomes and higher mortality from certain disorders despite having a lower (e.g. macrovascular complications of diabetes mellitus and osteoporotic fractures) or similar (e.g. thyroid cancer) incidence of these disorders. Obesity is an important contributor to diabetes risk in minority populations and to sex disparities in thyroid cancer, suggesting that population interventions targeting weight loss may favorably impact a number of endocrine disorders. There are important implications regarding the definition of obesity in different race/ethnic groups, including potential underestimation of disease risk in Asian-Americans and overestimation in non-Hispanic black women. Ethnic-specific cut-points for central obesity should be determined so that clinicians can adequately assess metabolic risk. There is little evidence that genetic differences contribute significantly to race/ethnic disparities in the endocrine disorders examined. Multilevel interventions have reduced disparities in diabetes care, and these successes can be modeled to design similar interventions for other endocrine diseases.

Melanoma in adolescents and young adults (ages 15-39 years): United States, 1999-2006

BACKGROUND

Invasive melanoma of the skin is the third most common cancer diagnosed among adolescents and young adults (aged 15-39 years) in the United States. Understanding the burden of melanoma in this age group is important to identifying areas for etiologic research and in developing effective prevention approaches aimed at reducing melanoma risk.

METHODS

Melanoma incidence data reported from 38 National Program of Cancer Registries and/or Surveillance Epidemiology and End Results statewide cancer registries covering nearly 67.2% of the US population were used to estimate age-adjusted incidence rates for persons 15-39 years of age. Incidence rate ratios were calculated to compare rates between demographic groups.

RESULTS

Melanoma incidence was higher among females (age-adjusted incidence rates = 9.74; 95% confidence interval 9.62-9.86) compared with males (age-adjusted incidence rates = 5.77; 95% confidence interval 5.68-5.86), increased with age, and was higher in non-Hispanic white compared with Hispanic white and black, American Indians/Alaskan Natives, and Asian and Pacific Islanders populations. Melanoma incidence rates increased with year of diagnosis in females but not males. The majority of melanomas were diagnosed on the trunk in all racial and ethnic groups among males but only in non-Hispanic whites among females. Most melanomas were diagnosed at localized stage, and among those melanomas with known histology, the majority were superficial spreading.

LIMITATIONS

Accuracy of melanoma cases reporting was limited because of some incompleteness (delayed reporting) or nonspecific reporting including large proportion of unspecified histology.

CONCLUSIONS

Differences in incidence rates by anatomic site, histology, and stage among adolescents and young adults by race, ethnicity, and sex suggest that both host characteristics and behaviors influence risk. These data suggest areas for etiologic research around gene-environment interactions and the need for targeted cancer control activities specific to adolescents and young adult populations.

Trends in incidence and survival of pediatric and adolescent patients with germ cell tumors in the United States, 1975 to 2006

BACKGROUND

Pediatric germ cell tumors (GCTs) are rare and heterogeneous tumors with uncertain etiology. In the current study, data from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program were used to evaluate trends in incidence and survival of GCTs in boys and girls ages ≤19 years. To the authors' knowledge, few studies to date have evaluated trends in pediatric GCTs. Results from these analyses may provide clues to the etiology of GCTs.

METHODS

Frequencies, incidence rates, and 5-year relative survival rates stratified by sex were evaluated overall and by demographic subgroups based on age (birth to 9 years and 10-19 years), race (white, black, and other), and ethnicity (non-Hispanic and Hispanic) as sample size permitted.

RESULTS

In whites, the incidence of GCTs was lower for females than males in the 10-year to 19-year age group (rate ratio [RR], 0.47; 95% confidence interval [95% CI], 0.42-0.53), whereas the rates were similar in the age group for birth to 9 years. In contrast, incidence rates were higher in black females than in black males in both age groups (RR, 2.01 [95%CI, 1.08-3.84] in those ages birth to 9 years; RR, 3.30 [95% CI, 2.13-5.28] in those ages 10-19 years). The incidence of ovarian GCT was significantly higher in Hispanic compared with non-Hispanic girls in the groups aged 10 to 19 years. Incidence rates increased during the study period in boys ages 10 to 19 years (annual percentage change [APC], 1.2; 95% CI, 0.4-2.1) and girls ages birth to 9 years (APC, 1.9; 95% CI, 0.3-2.5).

CONCLUSIONS

The incidence of pediatric GCTs in the United States appears to be increasing only in certain subgroups, suggesting that the etiology is not completely overlapping in all age groups. Differences in incidence patterns by race and ethnicity merit further investigation.

Ethnic and socioeconomic trends in testicular cancer incidence in New Zealand

Ethnic differences in testicular cancer incidence within countries are often sizeable, with white populations consistently having the highest ethnic-specific rates. Many studies have found that high socioeconomic status is a risk factor for testicular cancer. The objectives of this article are to test whether trends in testicular cancer incidence have varied by ethnicity and socioeconomic position in New Zealand between 1981 and 2004. Five cohorts of the entire New Zealand population for 1981-1986, 1986-1991, 1991-1996, 1996-2001 and 2001-2004 were created, and probabilistically linked to cancer registry records, allowing direct determination of ethnic and household income trends in testicular cancer incidence. There were more than 2,000 cases of testicular cancer over the study period. We found increasing rates of testicular cancer for all ethnic and income groups since 1990s. Maori had higher rates, and Pacific and Asian lower rates than European/other men with rate ratios pooled over time of 1.51 (95% CI 1.31-1.74), 0.40 (95% CI 0.26-0.61) and 0.54 (95% CI 0.31-0.94), respectively. Overall, men with low incomes had higher risk of testicular cancer than those with high incomes (pooled rate ratio for lowest to highest income groups = 1.23; 95% CI 1.05-1.44). There was no strong evidence that disparities in testicular cancer incidence have varied by ethnicity or household income over time. Given the lack of understanding of the etiology of testicular cancer, the unusual patterns identified in the New Zealand context may provide some etiological clues for future novel research.

Breast cancer before age 40 years

Approximately 7% of women with breast cancer are diagnosed before the age of 40 years, and this disease accounts for more than 40% of all cancer in women in this age group. Survival rates are worse when compared to those in older women, and multivariate analysis has shown younger age to be an independent predictor of adverse outcome. Inherited syndromes, specifically BRCA1 and BRCA2, must be considered when developing treatment algorithms for younger women. Chemotherapy, endocrine, and local therapies have the potential to significantly impact both the physiologic health-including future fertility, premature menopause, and bone health-and the psychological health of young women as they face a diagnosis of breast cancer.

Introduction to the supplement on cancer in the American Indian and Alaska Native populations in the United States

The collection of papers in this Supplement combines cancer incidence data from the National Program of Cancer Registries and the Surveillance, Epidemiology, and End Results program, enhanced by record linkages and geographic factors, to provide a comprehensive description of the cancer burden in the American Indian/Alaska Native population in the United States. Cancer incidence rates among this population varied widely, sometimes more than 5-fold, by geographic region.

Methods for improving cancer surveillance data in American Indian and Alaska Native populations

BACKGROUND

The misclassification of race decreases the accuracy of cancer incidence data for American Indians and Alaska Natives (AI/ANs) in some central cancer registries. This article describes the data sources and methods that were used to address this misclassification and to produce the cancer statistics used by most of the articles in this supplement.

METHODS

Records from United States cancer registries were linked with Indian Health Service (IHS) records to identify AI/AN cases that were misclassified as non-AI/AN. Data were available from 47 registries that linked their data with IHS, met quality criteria, and agreed to participate. Analyses focused on cases among AI/AN residents in IHS Contract Health Service Delivery Area (CHSDA) counties in 33 states. Cancer incidence and stage data were compiled for non-Hispanic whites (NHWs) and AI/ANs across 6 IHS regions of the United States for 1999 through 2004.

RESULTS

Misclassification of AI/AN race as nonnative in central cancer registries ranged from 85 individuals in Alaska (3.4%) to 5297 individuals in the Southern Plains (44.5%). Cancer incidence rates among AI/ANs for all cancers combined were lower than for NHWs, but incidence rates varied by geographic region for AI/ANs. Restricting the rate calculations to CHSDA counties generally resulted in higher rates than those obtained for all counties combined.

CONCLUSIONS

The classification of race for AI/AN cases in cancer registries can be improved by linking records to the IHS and stratifying by CHSDA counties. Cancer in the AI/AN population is clarified further by describing incidence rates by geographic region. Improved cancer surveillance data for AI/AN communities should aid in the planning, implementation, and evaluation of more effective cancer control and should reduce health disparities in this population.