Colorectal cancer disproportionally strikes some groups more than others.

By Claire Gillespie
August 31, 2020
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Actor Chadwick Boseman, best known as Black Panther in the Marvel Studios blockbuster of the same name, never made his 2016 stage 3 colon cancer diagnosis public. He continued to film movies, including Marshall and 21 Bridges, while having chemotherapy and undergoing surgeries. 

This made it even more devastating when Boseman’s family revealed his death. On August 29, a statement on the star’s Twitter page described him as “a true fighter” and “a global icon and an inspiring symbol of Black power.” 

Boseman was only 43 when he died, and his death brings an important issue to light: that rates of colon (colorectal) cancer are higher among younger Black men. Rates of colon cancer are 30% higher in men than in women of all races. And Black people have the highest rates of colon cancer of any racial or ethnic group in the US, according to the American Cancer Society (ACS).

During a four-year span from 2012-2016, colorectal cancer incidence rates in Black people were about 20% higher than those in non-Hispanic whites (NHWs) and 50% higher than those in Asian/Pacific Islanders (APIs). Mortality is higher too. Colon cancer death rates in Black people are almost 40% higher than the rates for NHWs and double the rates for APIs. 

While the overall numbers for colon cancer are going down, the instances of it in men under 50 are actually going up. In 2017, a large study of invasive colorectal cancers, funded by the ACS and published in the Journal of the National Cancer Institute, found that people born around 1990 have double the risk of developing colon cancer and quadruple the risk of developing rectal cancer compared with those born around 1950. This prompted the ACS to lower its recommended screening age for colorectal cancers from 50 to 45. 

Why are colon cancer rates disproportionately high in younger Black people?

Experts don’t really understand why colorectal cases in younger people are rising, Mark Pochapin, MD, director of gastroenterology at NYU Langone Health and president of the American College of Gastroenterology, tells Health. “The rates are going up by 2% per year, though the rates of occurrence are still nowhere near as high for people who are over the age of 65.” Some believe it might have to do with a change in the microbiome, which is the bacteria in the gut, from either using antibiotics or other environmental factors experts aren’t aware of, he adds.

The higher incidence in Black people is also difficult to explain. “This in part may be due to socioeconomics and access to health care, but there may be other factors that we just do not understand,” he says. 

Stacey Cohen, MD, a physician at Seattle Cancer Care Alliance and an associate professor in the division of medical oncology at University of Washington School of Medicine, believes that the high incidence and mortality rates in Black patients are due in part to the systemic racism that prevents earlier recognition of a medical condition.

“Colorectal cancer is thought of as a disease for older individuals, and so the diagnosis may be missed for months or years in a younger person,” adds Dr. Cohen. “Cancer is also difficult to detect at an early stage if a provider is not specifically evaluating for it.” 

What are the warning signs of colon cancer? 

In the very early stages, colon cancer typically doesn’t present any symptoms, because the tumor is small and causes no discomfort. “It can bleed as it grows, so people may see blood in their stool,” says Dr. Pochapin. “Additionally, the tumor can start to obstruct the opening of the colon, which can cause narrowing of the stool, making it look pencil-thin, or even cause difficulty passing it. Further, cancer can cause the development of pain and unexplained weight loss. There may also be unexplained anemia on a blood test that is caused by the chronic loss of blood.” 

Are there other risk factors for colon cancer?  

People with inflammatory bowel disease (IBD) are at higher risk for developing colon cancer, says Dr. Cohen. “There are some hereditary conditions that increase an individual’s risk, and a family history of colorectal cancer or precancerous polyps also increases an individual’s likelihood of developing cancer themselves," she adds.

Lifestyle factors that may increase the risk of colorectal cancers include a diet high in red meat and alcohol consumption, and low in fiber. 

“However, these factors do not predict or explain every case,” says Dr. Cohen. “This is why the number one thing we recommend is to undergo age-appropriate colorectal cancer screening and to discuss any concerning symptoms with your doctor.” 

What colorectal screening tests are available? 

Multiple screening tests are available for colorectal cancer. “The two most common are colonoscopy and something called ‘fecal immunochemical testing’ (FIT),” says Dr. Pochapin. 

A colonoscopy is a test done after a bowel prep, where you take a laxative to clean out the colon the night before. The next day, at a doctor’s office, procedure area, or hospital, a scope or instrument is inserted into the rectum while the patient is under sedation. 

“This travels through the colon looking for polyps," explains Dr. Pochapin, which are precancerous growths. “During the procedure we remove any that are found, so it is both diagnostic and also therapeutic—by removing the polyps we prevent the cancer. Of course colonoscopy also looks for early cancer, but the main purpose is prevention.”

FIT testing, on the other hand, is done at home, using a stick or small paintbrush to put a stool sample on a little card. This is sent to the lab to look for microscopic amounts of blood. 

“The concept here is that with early cancer, you will find trace amounts of blood in the sample,” says Dr. Pochapin. “If a FIT test is positive, the patient must get a colonoscopy relatively soon to make sure there isn’t a cancer causing the positive test. FIT testing looks for an early cancer, since it isn’t very good at finding polyps, and that’s why it’s more of a cancer detection test than a cancer prevention test, like colonoscopy.” 

Other tests include Cologuard, another type of stool test, which detects abnormal DNA, and virtual colonoscopy, which is performed with a CAT scan. 

At what age should I start colorectal cancer screening?

People who have a family history of colon cancer generally start testing 10 years earlier than the age at which the youngest person in the family who had cancer was diagnosed, says Dr. Pochapin. But it’s important to discuss that with your medical team because if there is clustering of family cancers, you may need to get genetically tested. Otherwise, he says everybody over age 50 should start screening. (But discuss with your doctor if you want to be screened earlier, because the ACS does recommend age 45.) 

“Black people should start screening at age 45 due to the higher incidence and higher mortality,” suggests Dr. Pochapin. “And if you already have symptoms, such as rectal bleeding, that’s no longer considered ‘screening’ but rather diagnostic. It’s very important to see a doctor to figure out why it’s happening.”   

If you’re younger than the recommended screening age but you have symptoms, then speak up. “Please advocate for yourself,” says Dr. Cohen. “If something doesn’t feel right for your body, discuss with your primary care provider whether a diagnostic colonoscopy should be done.” 

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