Disparities in Cancer Survival Seen in AIANs vs Whites

Pam Harrison

November 12, 2014

American Indians and Alaskan Natives (AIANs) with access to high-quality healthcare in urban settings have significantly lower survival rates 5 and 10 years after a cancer diagnosis than non-Hispanic whites with access to the same level of healthcare, preliminary findings show.

The study was presented at the American Association for Cancer Research conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held in San Antonio, Texas.

The patients in our study "were all members of the Kaiser Permanente Northern California [KPNC] health plan, so we know they all had access to high-quality healthcare," said Marc Emerson, MPH, a fellow at the National Cancer Institute in Bethesda, Maryland.

"But with the data analysis we are presenting here, we can say affirmatively that this group of AIANs experience worse 5- and 10-year survival rates following a cancer diagnosis than do non-Hispanic whites," he told Medscape Medical News.

"An important next step is to identify any potentially modifiable unique drivers of cancer-related disparities to inform potential interventions and policies aimed at reducing the observed differences in cancer-related mortality between AIANs and non-Hispanic whites," Emerson explained.

The investigators used the KPNC tumor registry and other electronic health records to gather data on 1022 AIAN and 139,725 non-Hispanic white patients diagnosed with primary invasive cancer from 1997 to 2012.

Information on race, cancer site, tumor size, tumor grade, stage, year of diagnosis, age at diagnosis, type of treatment, comorbidities, follow-up interval, and sociodemographic characteristics was documented.

Patients were followed from the date of diagnosis to death from any cause, study withdrawal, or the end of the study period (March 31, 2014), whichever came first.

The incidence of the four most common cancer diagnoses differed slightly, depending on the patient's ethnic background.

Table. Incidence of the Four Most Common Cancer Diagnoses

Cancer AIAN Patients, % Non-Hispanic White Patients, %
Prostate 16.4 17.3
Breast 16.4 16.8
Lung 13.3 11.7
Colorectal 12.5 9.3

 

The fifth most common cancer diagnosed in AIAN patients was non-Hodgkin's lymphoma, at 4.0%, and in non-Hispanic white patients was melanoma, at 6.6%.

Survival Estimates

Estimated survival rates for any cancer were significantly lower in AIAN patients than in non-Hispanic white patients at 5 years (51.9% vs 58.2%; P < .001) and at 10 years (37.4% vs 43.8%; P < .001).

Both 5- and 10-year survival estimates were consistently lower in AIAN than in non-Hispanic white patients for the most common individual cancer sites. However, the difference was only significant for the 5-year survival rate for breast cancer patients.

Although comorbidities were similar in the two groups, and included chronic pulmonary disease, diabetes, and congestive heart failure, rates were significantly higher in AIAN than in non-Hispanic white patients (P < .003).

"Initial treatment, including radiation therapy and chemotherapy, look similar between the two groups. At this point in our analysis, we are not able to examine whether completion of these therapies varies between the AIANs and non-Hispanic whites," Emerson noted.

"But there may be underlying personal issues that influence how AIANs utilize healthcare — the ability to take time off work, for example, preferences when it comes to treatment, and even patient–provider communication," he explained.

"These are the kinds of questions that will be important to address moving forward as we continue to research this population," he said.

The study was funded by the National Cancer Institute. Marc Emerson has disclosed no relevant financial relationships.

Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved: Abstract B39. Presented November 11, 2014.

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