Researchers investigated medical records on nearly 29,000 American Indians and Alaska Natives who had been diagnosed with cancer between 1999 and 2004.
The study shows Indians in this region have significantly higher rates of several types of cancer. The rate of liver cancer for Indians is 197 percent higher than for non-Hispanic whites and their rate for gallbladder cancer is 148 percent higher.
David Perdue is a physician and researcher at the University of Minnesota's Masonic Cancer Center. Perdue was the lead author on a portion of the study that focused on colorectal cancer. Perdue said the research shows cancer prevention among American Indians should be a top priority.
"I think they show tremendous disparities in cancer for many American Indian populations throughout the country," Perdue said. "It really points to the fact that we need to try to engage health systems to take on cancer disparities."
The study shows cancer rates for American Indians vary widely based on where they live.
Southwestern tribes, for example, have colorectal cancer rates that are half that of the local white population. But, for tribes on the Northern Plains and in Alaska, the colorectal cancer rate is 40 to 50 percent higher than whites in the region.
David Perdue said the cause of high cancer rates among Indians in the north isn't clear, but probably includes factors like diet, genetics and higher rates of smoking.
"American Indians tend to have a higher burden of many risk factors for cancer," he said. Perdue also said poverty, obesity and diabetes can all be risk factors.
"Not getting screening procedures is a risk factor too," Perdue said.
Perdue is also concerned about access to adequate health care. The federal Indian Health Service provides health care for about half of American Indians in the country, but Perdue said the agency is chronically underfunded.
"Current funding levels per capita for Indian Health Service are about half of what the government spends on Medicare funding and about half what they spend per capita on incarcerated persons in the prison system," he said.
Many of the cancers highlighted in the study are preventable. Judith Kauer, director of Native American Programs at the Mayo Clinic's Cancer Center in Rochester, co-authored several sections of the study. Kauer said the new data suggests the need for more resources for cancer screening and better prevention education among tribal members.
"Certainly, there needs to be awareness on the community level," Kauer said. "It is a wake-up call that we can be doing better and that communities should galvanize around cancer control issues."
Indian Health Service officials say their constant funding struggles make it difficult to provide what's needed for adequate cancer prevention in Indian Country.
Kathleen Annette, director of an IHS region that includes Minnesota, Wisconsin and Michigan, said the agency does what it can.
"When resources are limited, you tend to start prioritizing what you provide," Annette said. "But as funding becomes scarcer, you tend to prioritize to life or death situations."
Annette said she hopes the new study will get the attention of tribal members and get them to consider making healthy lifestyle changes.
"The new information has great, profound impacts on individual people," she said. "It's your mother, your father, yourself, your children, that are at risk and can indeed experience this. It's so important to learn as much as you can and take advantage of the screening opportunities that are there."
The cancer study was sponsored by the National Cancer Institute, the Centers for Disease Control and Prevention and Indian Health Service. The findings will be published September 1, 2008, in "Cancer," a medical journal published by the American Cancer Society.