Although colorectal cancer is the fourth most commonly diagnosed cancer in the U.S., it’s also one of the most preventable types of cancers. However, colon cancer doesn’t affect all people equally. In fact, the incidence and prognosis for CRC in African-Americans is much less favorable than other populations. Many factors contribute to these differences.
[See: 8 Questions to Ask Your Doctor About Colon Cancer.]
What the Data Show
When you compare colorectal cancer rates in African-Americans in the U.S. to Africans, there are substantial differences even though they share about 80 percent of their genetic material, says Dr. Ezra Burstein, division chief of digestive and liver diseases at UT Southwestern Medical Center. In South Africa, for example, fewer than 5 in every 100,000 people develop CRC, Burstein says. On the other hand, in the U.S., 50 to 60 African-Americans out of every 100,000 develop the disease.
“It’s not just genetics,” Burstein says. “There’s a big environmental role [as well]. In North America, lifestyle factors such as diet, rates of obesity, smoking and lack of exercise may unleash a type of tumor that may not occur in healthy people.” As other countries become more westernized in terms of diet and lifestyle, cancers of the gastrointestinal tract, especially colorectal cancer, have become the No. 1 type of cancer in the world.
African-Americans are more likely to develop CRC at a younger age and to be at a more advanced stage when diagnosed. According to the National Cancer Institute, even when African-Americans are diagnosed with early stage disease, they have significantly worse survival rates. And, although the overall colorectal cancer incidence among people 50 and older has declined over the past decade, in large part because of screening, the NCI says incidence and mortality are highest among African-Americans.
[See: 10 Seemingly Innocent Symptoms You Shouldn’t Ignore.]
There are several ideas to explain these disparities. The first is access to care. “Screening rates are much lower than they should be,” says Dr. Dale R. Shepard, a medical oncologist at the Cleveland Clinic. “Far too few [African-Americans] are getting screening.”
This is a complicated social issue. In some cases, low screening is due to lack of access in medically underserved areas (lack of access to care also contributes to poor prognosis even after you’re diagnosed). In other cases, it’s lack of awareness. “Awareness of the problem [of CRC] is a big issue,” Burstein says. “Even if you have access, if you are not aware, you’re not taking advantage of lifesaving screening. African-Americans who have a family history of CRC [a significant risk factor] are less likely to get screened.”
The types of colorectal cancer tumors that African-Americans develop are also different. First of all, they’re more likely to have tumors that develop in the right side of the colon. These right-sided tumors are associated with poorer outcomes, regardless of race or ethnicity. Colonoscopy, a type of cancer screening that looks at the full length of the colon, helps catch these right-sided tumors.
The NCI says there is also preliminary evidence that CRC tumors in African-Americans are more likely to have molecular characteristics associated with worse outcomes than CRC tumors in whites and Hispanics, including mutations in a specific gene, KRAS, that affects a cell’s ability to repair errors during DNA replication.
How to Level the Playing Field
Burstein says when you look at the burden of colorectal cancer in the general population and realize it’s the most preventable type of cancer with appropriate screening, it really highlights the disparities between African-Americans and other populations.
“Early diagnosis is huge,” Shepard says. If you find CRC in the early stage and remove it, the chance you will still be alive in 10 years is 90 percent. If you have metastasized CRC [cancer that has spread], your chance of being alive in 10 years is 10 percent. We need to catch CRC at an early stage.”
Some medical organizations and doctors recommend that African-Americans begin screening at age 45 instead of 50, which is the general recommended age for people at average risk. This recommendation is not universally accepted, Burstein says. The thinking is that because it takes about a decade for a benign polyp in the colon to develop into cancer, catching polyps in African-Americans who are in their 40s can help prevent later stage colorectal cancer diagnoses.
[See: Creative Ways Hospitals Reach Diverse Populations.]
We know that improving access to screening works. When cities or systems provide equal access to CRC screening, racial and ethnic disparities in colon cancer are significantly reduced. Shepard says at the Cleveland Clinic, where he practices, there’s been an amazing response to minority men’s health fairs. “We literally have people lined up out the door to get more involved in health and screening,” he says.
If you’re African-American, talk to your doctor about your risks and screening for colorectal cancer.
More from U.S. News
8 Questions to Ask Your Doctor About Colon Cancer
6 Options for People Who Don’t Want a Colonoscopy
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Why Are African-Americans at Greater Risk for Colorectal Cancer? originally appeared on usnews.com
