Survival among Native American Adolescent and Young Adult Cancer Patients in California

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1 Survival among Native American Adolescent and Young Adult Cancer Patients in California Cyllene R. Morris, 1 Yi W. Chen, 1 Arti Parikh-Patel, 1 Kenneth W. Kizer, 1 Theresa H. Keegan 2 1 California Cancer Reporting and Epidemiologic Surveillance (CalCARES) Program, Institute for Population Health Improvement, UC Davis Health 2 Division of Hematology and Oncology, UC Davis Comprehensive Cancer Center

2 California Native Americans (NA) Native American (American Indians/Alaska Natives) population in California: largest in the US 1:7 identified NA in the US lives in California Over 75% in urban areas Very diverse population: 109 Federally recognized tribes, 78 seeking recognition Little tribal land owned, only 3% live in reservations

3 US Native Americans health disparities Long history of struggle and hardship Substantial health disparities High rates of poverty, unemployment, chronic diseases High prevalence of drinking, smoking, obesity Overall lower life expectancy Lower cancer screening, late stage at DX, lower cancer survival

4 Health care: complex, underfunded, legal right I/T/U system: IHS/Tribal/Urban (unique funding streams) NA status: confirmation by tribe (not self identified)! Four main sources for cancer care: Indian Health Services (IHS) direct care (no IHS hospitals in CA) Contract Health Services (CHS): in CA, mostly tribe-operated Eligibility: residence in reservation or within CHS delivery areas (CHSDA) Contracted services not authorized if other options exist Medicaid (or Medicare) Private Insurance

5 Contract Health Services Delivery Area (CHSDA) CHSDA: counties that include all or part of a reservation or share common boundary May be established based on: NA population in area Determination that NA living in area are socially and economically affiliated with the tribe 58 counties in California: 38 CHSDA (28% CA population) 20 non-chsda (72% CA population)

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7 Cancer in adolescents and young adults (AYA) AYA (15-39 years old): population group least likely to be insured Cancer burden information lacking in this underserved population Most common cancers in this age group: Breast Leukemia Cervix Hodgkin Lymphoma Ovary NH Lymphoma Testis Brain & CNS Colon and rectum Sarcomas Melanoma Thyroid

8 Assess the impact of selected factors on survival (adjusting for sex, age, cancer site, and late stage at DX) Type of insurance Race/ethnicity Residence in rural areas or in CHSDA counties SES Study Objectives Describe adolescents and young adults (AYA) Native Americans diagnosed with cancer in California Characterize survival differences among NA-AYS cancer patients compared with other racial/ethnic groups

9 Methods

10 Study population AYA California residents Diagnosed with 12 most common cancers in AYA California Cancer Registry data linked with IHS files AYA cases linked with Medicaid enrollment files Native American: race in record or IHS-linked

11 Statistical Analysis Frequency distributions and bivariate associations Scope limited by small number of NA cases (NA) Multivariate Cox proportional hazards models to estimate Hazard Ratios (HR) and 95% CI

12 Definition of Variables Late stage: regional/distant disease Rural/Urban: defined by Medical Service Study Areas Health Insurance classified as: Medicaid (linkage-confirmed) IHS/Public Uninsured Private/military (referent group) SES: CCR-developed Yost/Yang score (7 factors selected from principal components analysis)

13 Results

14 AYA cancer cases in California: characteristics NA Black Hispanic Asian/PI NH White Cases 417 3,197 22,558 7,663 29,137 Median Age % Late Stage DX % Rural Residence % in CHSDA County SES: % Low-Mid % Middle % Mid-High Insurance: % Private Public % Medicaid % IHS/

15 AYA Cancer Patients Vital Status (date last contact) Cancer Site White Native American DX Cases % Alive Cases % Alive Breast 4, Cervix 1, Testis 3, Colon & Rectum 1, Melanoma 5, Brain & CNS 1, Hodgkin Lymphoma 2, Non-Hodgkin Lymphoma 1, Leukemia 1, Sarcomas 1, TOTAL 23,

16 Cox Adjusted Hazard Ratios (1) Covariates HR 95% CI Female (vs. Male) 0.71 * 0.68, 0.74 Age (years) 1.02 * 1.02, 1.03 Late Stage (Y/N) 3.46 * 3.29, 3.64 SES Score (1: low, 5: high ) 0.94 * 0.92, 0.95 Rural (vs. Urban) , 1.02 CHSDA county (vs. not) 1.10 * 1.05, 1.15 * P < 0.05 Adjusted for cancer site

17 Cox Adjusted Hazard Ratios (2) Covariates HR 95% CI Insurance (Ref: private/military) Medicaid 2.05 * 1.95, 2.15 IHS/Public 1.38 * 1.19, 1.60 Uninsured 1.34 * 1.19, 1.50 Race/Ethnicity (Ref: NH white) Native American 1.31 * 1.05, 1.62 Black 1.56 * 1.43, 1.68 Hispanic 1.07 * 1.02, 1.13 Asian/Pacific Islander 1.17 * 1.09, 1.26 * P < 0.05 Adjusted for cancer site

18 Cox Hazard Ratios: cancer sites with 25 cases Site NA Black Hispanic Asian/PI Breast * Cervix * Testis * 1.42* 1.86* Colon & Rectum * Melanoma * Brain & CNS * Leukemia * 1.02 Sarcomas 2.53* 1.46* 1.19* 1.32* p < 0.05 Adjusted for age, sex, stage, rural residence, CHSDA county, SES, insurance

19 Among Native Americans only Characteristic HR 95% CI Female (vs. male) , 1.19 SES Score (1-5) , 1.17 Insurance (ref: private/ military) Medicaid , 2.59 IHS , 3.35 Uninsured , 6.29 In CHSDA County (y/n) 0.55 * 0.34, 0.90 * P < 0.05 Adjusted for age, stage, cancer site

20 Social Aspects Indian Relocation Act increased NA population in urban areas (devastating long-term effects) Urban environment outside tribal communities a challenge for many young NA Smaller and dispersed population makes it difficult to find peer subgroups

21 Why better survival in CHSDA counties? Even when referred out for cancer treatment, NA living in CHSDA counties eligible for IHS services: Access to clinical care beyond cancerspecific treatment? Life in CHSDA counties: better social support system and more cultural connection?

22 Conclusions: Among AYA of all race/ ethnicities Compared to whites - NA, blacks and Hispanics more likely to: Diagnosed at late stage disease (also Asian/PIs) Live in lower SES areas Be insured by Medicaid For all racial/ethnic groups: cancer survival significantly lower than whites

23 Conclusions: Among Native American AYA Overall cancer survival significantly lower than whites (but not for all cancer sites) Mortality risk much higher for sarcomas (almost 2X all other groups) Disparities in insurance/ses: somewhat in between (1) blacks-hispanics and (2) whites-asian/pis Life in CHSDA counties associated with longer survival

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