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.

Impact of skeletal-related events on survival in patients with prostate cancer metastatic to bones

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Background: Skeletal related events (SREs), defined as pathological fracture, spinal cord compression, surgery or radiotherapy to the bone, occur in nearly half of men diagnosed with metastatic prostate cancer. Accurate assessment of the risk of death associated with SREs is important to making decisions about the use of recently approved treatments, which have been shown to decrease the frequency of skeletal events, yet estimating the impact of SREs on survival presents several methodological challenges given the recurrent time-dependent nature of exposure. Methods: A cohort of men >65years of age, diagnosed with prostate cancer and bone metastasis between January 1, 2004 and December 31, 2009 was identified from the Surveillance Epidemiology and End Results (SEER) registries were linked to Medicare Parts A and B claims. The outcome of interest, death from any cause, was ascertained from SEER and survival time was calculated from the date of metastatic prostate cancer diagnosis. Multivariable Cox proportional hazards models treating the occurrence of an SRE as a time-dependent exposure were used to estimate the hazard ratios (HR) and corresponding 95% confidence intervals (CI) for the association between SRE occurrence, number, and type, and death. Results: Among 3,297 men with metastatic prostate cancer, 40% experienced ≥1 SRE during the observational follow-up period (median 19 months). Compared to men who remained SRE-free, cohort members who had ≥1 SREs had a two-fold higher risk of death (HR 2.2, 95% CI 2.0-2.4). Those whose first SRE was a pathological fracture had a 2.7-fold higher risk of death (HR 2.7, 95% CI 2.3-3.1), followed by spinal cord compression (HR 2.1, 95% CI 1.8-2.5), surgery (HR 1.8, 95% CI 1.5-2.2) and radiotherapy (HR 2.2, 95% CI 1.9-2.4). Compared to those experiencing only one SRE, men who experienced a second SRE of any type had double the risk of death (HR 2.2, 95% CI 1.9-2.6). Conclusions: SREs were associated with ≥50% reduction in overall survival. This finding is consistent across different types of SREs and supports using therapies to prevent or treat SREs in patients with prostate cancer metastatic to the bones.

Performance of a low-dose computed tomography (LDCT) lung cancer screening program: Findings from a registry study

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Background: Many centers are establishing LDCT lung cancer screening programs after the 2013 grade B recommendation from the United States Preventive Services Task Force (USPSTF). Uncertainty remains regarding the extent to which new programs will adhere to recommended selection criteria, as well as screening program performance. We analyzed adherence to selection criteria, rate of positive screens, and prevalence of incidental findings in a single-center LDCT screening registry study. Methods: We established a prospective, longitudinal registry study of patients undergoing LDCT screening at the Seattle Cancer Care Alliance. Baseline data include socio-demographic characteristics and eligibility for LDCT screening. We conduct chart reviews at 6 and 12 months to determine screening results (based on NLST definitions); lung cancer diagnosis; and incidental findings. Results: From August 2012 to April 2014, 62 out of 105 (59%) screened patients enrolled in the registry. Mean age is 62 years; 38 (61%) are male; 52 (84%) are white; mean household income is $97,363; 31 (50%) are current smokers; and 39 (63%) have a smoking history ≥ 30 pack-years. A total of 28 (45%), 31 (50%), and 31 (50%) of patients were eligible for screening based on criteria used in the NLST or recommended by the NCCN or USPSTF guidelines, respectively. Sixteen patients (26%) were not eligible for screening based on any of these criteria. For fourteen (88%) of these patients, LDCT screening was ordered by a primary care provider as opposed to a lung cancer specialist. Initial screening results were positive in 7 (13%) patients, with 1 patient diagnosed with lung cancer. At least one incidental finding was reported in 40 (74%) patients, including cardiac and pulmonary abnormalities in 28 (70%) and 25 (63%) patients. Conclusions: About one quarter of patients undergoing LDCT screening do not meet recommended criteria, with primary care providers most commonly ordering the LDCT screen for these patients. Primary care provider education may improve adherence to screening guidelines. Incidental findings were more frequently reported than in the NLST; their impact on healthcare outcomes and costs deserves further investigation.