Indian Health Service Care System and Cancer Stage in American Indians and Alaska Natives.

PURPOSE: We aimed to determine whether the association between late-stage cancer and American Indian/Alaska Native (AI/AN) race differed by enrollment in the Indian Health Service Care System (IHSCS). METHODS: We used Surveillance, Epidemiology, and End Results (SEER) data linked to Medicare files to compare the odds of late-stage breast, colorectal, lung, or prostate cancer between non-Hispanic Whites (NHWs) (n=285,993) and AI/ANs with (n=581) and without (n=543) IHSCS enrollment. RESULTS: For AI/ANs without IHSCS enrollment, the odds of late-stage disease were higher in AI/ANs compared with NHWs for breast (OR=3.17, 95%CI: 1.82-5.53) and for prostate (OR=2.59, 95%CI:1.55-4.32) cancer, but not for colorectal or lung cancers. Among AI/ANs with IHSCS enrollment, there was not a significant association between late-stage disease and AI/AN race for any of the four cancers evaluated. CONCLUSION: Our results suggest that enrollment in the IHSCS reduced the disparity between AI/ANs and NHWs with respect to late-stage cancer diagnoses.

Cancer Treatment Delays in American Indians and Alaska Natives Enrolled in Medicare.

To assess whether timing of initial post-diagnosis cancer care differs between American Indian and Alaska Native (AI/AN) and non-Hispanic White (NHW) patients, we accessed SEER-Medicare data for breast, colorectal, lung, and prostate cancers (2001-2007). Medicare claims data were examined for initiation of cancer-directed treatment. Overall, AI/ANs experienced longer median times to starting treatment than NHWs (45 and 39 days, p < .001) and lower rates of treatment initiation (HR[95%CI]: 0.86[0.79-0.93]). Differences were largest for prostate (HR: 0.80[0.71-0.89]) and smallest for breast cancer (HR: 0.96[0.83-1.11]). American Indians / Alaska Natives also had elevated odds of greater than 10 weeks between diagnosis and treatment compared with NHWs (OR[95% CI]: 1.37[1.16-1.63]), especially for prostate cancer (OR: 1.41[1.14-1.76]). Adjustment for comorbidity and socio-demographic factors attenuated associations except for prostate cancer. In this insured population, we observed evidence that AI/ANs start cancer therapy later than NHWs. The modest magnitude of delays suggests that they are unlikely to be a determinant of survival disparities.

Cancer Stage in American Indians and Alaska Natives Enrolled in Medicaid.

INTRODUCTION: Nationally, a greater proportion of American Indians and Alaska Natives (AI/ANs) are diagnosed with advanced-stage cancers compared with non-Hispanic whites. The reasons for observed differences in stage at diagnosis between AI/ANs and non-Hispanic whites remain unclear. METHODS: Medicaid, Indian Health Service Care Systems, and state cancer registry data for California, Oregon, and Washington (2001-2008, analyzed in 2014-2015) were linked to identify AI/ANs and non-Hispanic whites diagnosed with invasive breast, cervical, colorectal, lung, or prostate cancer. Logistic regression was used to estimate ORs and 95% CIs for distant disease versus local or regional disease, in AI/ANs compared with non-Hispanic white case patients. RESULTS: A similar proportion of AI/AN (31.2%) and non-Hispanic white (35.5%) patients were diagnosed with distant-stage cancer in this population (AOR=1.03, 95% CI=0.88, 1.20). No significant differences in stage at diagnosis were found for any individual cancer site. Among AI/ANs, Indian Health Service Care Systems eligibility was not associated with stage at diagnosis. CONCLUSIONS: In contrast to the general population of the U.S., among Medicaid enrollees, AI/AN race is not associated with later stage at diagnosis. Cancer survival disparities associated with AI/AN race that have been observed in the broader population may be driven by factors associated with income and health insurance that are also associated with race, as income and insurance status are more homogenous within the Medicaid population than within the broader population.

Cancer-Directed Therapy and Hospice Care for Metastatic Cancer in American Indians and Alaska Natives.

BACKGROUND: Little has been reported regarding patterns of oncologic care in American Indian/Alaska Natives (AI/AN). Observed worse survival has been attributed to later-stage presentation. We aimed to evaluate racial differences in cancer-directed therapy and hospice care utilization in AI/ANs and non-Hispanic whites (NHW) with metastatic cancer. METHODS: The linked Surveillance, Epidemiology, and End Results (SEER)-Medicare claims database was accessed for AI/AN and NHW metastatic-cancer cases diagnosed between 2001 and 2007. Utilization of cancer-directed therapy (surgery, radiation, and/or chemotherapy) and/or hospice services was compared between AI/ANs and NHWs. Minimally adjusted (age, sex, diagnosis year) and fully-adjusted (also Klabunde comorbidity score, sociodemographic factors) regression models were used to estimate odds (OR) and hazard ratios (HR) for receipt of care. RESULTS: AI/ANs were younger, more likely to reside in the West, be unmarried, have lower income, and live in a nonurban setting than NHWs. Fewer AI/ANs received any cancer-directed therapy (57% vs. 61% NHWs) within 3 months of diagnosis; sociodemographic factors accounted for much of this difference [fully-adjusted HR, 0.94; 95% confidence interval (CI), 0.83-1.08]. We noted differences in hospice utilization between AI/ANs (52%) and NHWs (61%). A significant difference in hospice utilization remained after adjustment for sociodemographics (OR, 0.78; 95% CI, 0.61-0.99). CONCLUSION: Observed absolute differences in care for AI/ANs and NHWs with metastatic cancer were largely accounted for by adjusting for socioeconomics, comorbidities, and demographic factors. A significant association between race and hospice utilization was noted. IMPACT: Efforts to improve metastatic-cancer care should focus on socioeconomic barriers and investigate the observed disparity in receipt of hospice services.