What is ANTHC doing about colorectal cancer among Alaska Native people?March 7, 2018
March is Colorectal Cancer Awareness Month; colorectal cancer is one of the most frequently diagnosed cancers among Alaska Native people. This story can also be found in the current issue of the Mukluk Telegraph.
We are tackling colorectal cancer (CRC) through research.
Alaska Native people have the highest reported rates of CRC in the world. ANTHC is working to find out why. Below are descriptions of CRC studies at ANTHC and their findings and/or what they hope to learn.
Measuring the impact of lowering the age of first colorectal cancer screening to 40 in Alaska Native people
Alaska Native people have higher rates of CRC at younger ages than the general U.S. population. Screening colonoscopy is currently the gold standard for finding and removing precancerous colon polyps. Since 2013, ANTHC has recommended screening colonoscopy beginning at age 40. This is ten years earlier than what is recommended for the general U.S. population. This study looks at patient medical records to see if screening at an earlier age has resulted in better outcomes for Alaska Native people.
Improving colorectal cancer screening among Alaska Native people using the stool DNA test
Screening for CRC can prevent cancer or find it early when it is more easily treated. Stool DNA testing (Cologuard) is a new CRC screening test. This study is asking patients and providers at three regional Tribal health organizations what they think of using the stool DNA test compared to colonoscopy.
Diet, the microbiota and colon cancer risk in Alaska Native people
Diet affects the kinds of bacteria living in the colon. This study looked at the bacteria in the stool samples of healthy Alaska Native people and the substances made by those bacteria when they breakdown food in the colon. Some of the bacteria and substances help the tissue cells of the colon stay healthy; other kinds of bacteria irritate the cells lining the colon. This might be how many colon cancers start. We compared these findings to studies of Africans living in Africa because their rates of colon cancer are low and their diets are high in fiber. The results showed that the stool of Africans had more of the healthy bacteria and substances that protect the colon than among Alaska Native people.
Is it fiber that reduces the risk of colon cancer?
As we learned in the pilot study, Alaska Native people had higher levels of harmful bacteria and substances in the gut than Africans who eat a lot of fiber and have very low rates of colon cancer. This study will see if we find healthier bacteria and healthier colons if our sample of Alaska Native people eats more fiber.
Fecal immunochemical testing for cancer screening among Alaska Native people
This study compared two types of CRC screening tests: FIT (fecal immunochemical test) and fecal occult blood test (gFOBT). The study found that FIT was better at finding CRC and precancerous colon polyps than gFOBT. When study results were shared with Alaska Native Medical Center leadership, it was decided to include FIT in the list of screening tests recommended for Alaska Native people.
Improving colorectal cancer screening among Alaska Native people using the stool DNA test: An initial appraisal
This study compared two types of CRC screening tests: FIT (fecal immunochemical test) and Cologuard (stool DNA test). The study found that the Cologuard test was better at finding CRC and precancerous colon polyps than FIT. These study results were shared with the United States Preventive Services Task Force, which made the decision to include Cologuard in the list of nationally recommended screening tests.
Understanding risk protective factors for colorectal cancer among Alaska Native people
We are not sure if the factors that cause, and protect from, colorectal cancer are similar among Alaska Native people to other people that have been studied. This study will look at several different factors — diet, smoking, physical activity, lifestyle, and genetics — to see if they are related to CRC among Alaska Native people.
If you have questions about any of these research studies or if you have ideas for other studies, please contact Dr. Timothy Thomas, Director of ANTHC Research at tkthomas@ anthc.org.
Related story: Demystifying the colonoscopy