U of M study finds higher cancer rates among American Indians

(August 20, 2008) – The first large-scale national study of cancer rates among American Indians and Alaska Natives shows that American Indians living in Minnesota and the surrounding Northern Plains have a 39 percent higher rate of colorectal cancer than non-Hispanic whites. Related studies indicate that American Indians in this region also have a 197 percent higher rate of liver cancer, 135 percent higher rate of stomach cancer, and 148 percent higher rate of gallbladder cancer than non-Hispanic whites.

David Perdue, M.D., physician-researcher with the Masonic Cancer Center, University of Minnesota, is the lead author of the research study on the incidence rates of colorectal cancer and co-author of the studies on the rates of stomach, liver, and gallbladder cancer among American Indians and Alaska Natives. The findings of the four studies are published online today by the journal Cancer and will be published as a special supplement in the print edition of the journal on Sept. 1, 2008. Cancer is published by the American Cancer Society.

“All of these cancer rates are concerning, but of serious concern to Minnesota and other Northern Plains tribes is the higher rate of colorectal cancer as it is the second most common cause of cancer deaths in the United States behind lung cancer,” said Perdue, who specializes in research on preventing cancers of the intestinal tract in American Indian and Alaska Native populations. He also is co-chairman of the Minnesota Colorectal Cancer Task Force and a member of the Chickasaw Nation of Oklahoma.

“The causes for the high rate of colorectal cancer in the Northern Plains are less clear and most likely are due to a number of factors including diet, genetic makeup, non-traditional tobacco use, diabetes, and environmental factors,” Perdue said. “What is clear, however, is that education about lifestyle changes coupled with screening detection programs can prevent a majority of these cancers. Finding resources and working with American Indian communities and their health care providers to encourage screening participation needs to be a major health priority.”

Perdue and his research colleagues worked with the National Cancer Institute, the Center for Disease Control and Prevention, and the Indian Health Service, as well as state cancer data collection divisions throughout the United States. Together, they gathered information on cancer rates among American Indians and Alaska Natives in the Northern Plains, Southern Plains, Pacific Coast, East, and Southwest of the United States and among people native to Alaska. (Minnesota researchers working with Perdue included Carin Perkins, Ph.D., Minnesota Department of Health in Minneapolis, and Judith Kaur, M.D., Mayo Clinic in Rochester.)

The researchers investigated medical records of nearly 29,000 American Indians and Alaska Natives who had been diagnosed with cancer between 1999 and 2004. They noted the type of cancer each individual was diagnosed with, the stage of the cancer at the time of diagnosis, the treatment received, and the outcome. They then compared the data to the same information on non-Hispanic whites.

Other highlights of their findings include:

• For all cancers combined: Incidence rates among American Indians in the Southwest, the Plains and for Alaska Natives were 50 percent higher than the rates for non-Hispanic whites.
• Lung cancer: American Indians in the Northern Plains had the highest rates followed by Alaska Natives. The lowest rates were among American Indians in the Southwest.
• Breast cancer: The highest rates were among Alaska Native women. American Indian women in the Northern and Southern Plains had rates similar to or slightly lower than non-Hispanic white women. The lowest rates were among American Indian women in the Southwest; their rate was less than half of non-Hispanic women. In all regions, American Indian and Alaska Native women were more likely to be diagnosed with more advanced breast cancer compared to non-Hispanic white women.

“American Indians and Alaska Natives in many areas face significant risk factors for many types of cancer, and significant barriers to early detection and treatment,” Perdue said. “The result is higher cancer rates, and cancer being diagnosed in later, more difficult to survive stages.

“It is evident from this research that much more needs to be done to close the disparity gap in cancer screening and treatment among American Indians and Alaska Natives,” Perdue added. “Resources and culturally-sensitive programs aimed at decreasing risk factors and increasing the use of screening are desperately needed.”

These research studies were sponsored by National Cancer Institute, the Centers for Disease Control and Prevention, and Indian Health Service. For a complete analysis of the cancer rates, see the online version of the journal Cancer: http://www.interscience.wiley.com/cancer.)

About the Masonic Cancer Center
The Masonic Cancer Center at the University of Minnesota is part of the University’s Academic Health Center. It is a Comprehensive Cancer Center designated by the National Cancer Institute for cancer research, treatment, and education. For more information visit www.cancer.umn.edu or call 612-624-2620.

Contact: Mary Lawson, Masonic Cancer Center, 612-624-6165
Sara Buss, Academic Health Center, 612-626-7037