When Should You Get Screened for Colon Cancer?
Research shows that rates of colorectal cancer are increasing in U.S. adults under the age of 55.
While the recommended screening age is 45, experts say people who are at high risk of colorectal cancer should seek testing sooner.
The presence of certain symptoms might also alert someone to get screened, even if they're younger than 45.
Colorectal cancer diagnoses are surging at an alarming rate among younger adults in the United States.
In 2023, around 153,020 individuals will be diagnosed with colorectal cancer, according to estimates from a new report published by the American Cancer Society. Of these cases, nearly 13% would be among people younger than 50, and 3,750 of them would die from the disease.
The proportion of colorectal cancer diagnoses among people under 50 doubled between 1995 and 2019, from 11% to 20%.
Although current guidelines recommend screening for colorectal cancer at the age of 45, experts say that some high-risk individuals should get screened earlier.
Related:Differences Between Colorectal and Colon Cancer
Should You Screen for Colorectal Cancer Earlier?
Genetic testing is one way to determine whether you have genes that predispose you to colorectal cancer, according to Richard Goldberg, MD, professor emeritus at the West Virginia University Cancer Institute.
“The highest risk groups are those that have inherited cancer susceptibility syndromes such as Lynch syndrome,” Goldberg told Verywell. “Several other syndromes are associated with the development of polyps, including familial adenomatous polyposis (FAP), for example.”
Anyone with a family history of colorectal cancer, especially in a first-degree relative—such as sibling, parent, or offspring—can also indicate that someone has a higher risk than average, even more so if there’s a case among a younger family member. In this case, you might want to start screening 10 years before the age at which your youngest affected relative was diagnosed, Goldberg said.
Chronic inflammation of the colon and rectum can also predispose someone to developing colorectal cancer, Goldberg explained. Crohn’s disease and ulcerative colitis—especially in cases that aren’t well controlled by treatment or in those who’ve been symptomatic for decades—may also increase the risk of colon cancer.
Doctors will begin screening individuals with known cancer predisposition syndromes like Lynch syndrome or familial polyposis syndrome as early as their mid-teens, Goldberg said, because cancers can develop in these individuals in adolescence or young adulthood. The same is true for individuals with Crohn’s disease and ulcerative colitis.
Related:Risks of Untreated Crohn's Disease
What Other Factors Might Put You at Risk of Colorectal Cancer?
Ethnicity is another factor that's associated with colorectal cancer risk, according to Goldberg. In the U.S., for example, Yupik Eskimos have the highest prevalence of the disease and higher death rates than the general population.
“This is likely a combination of genetic and environmental factors,” he said. “Dietary choices available to Indigenous people living in a cold environment generally focus on marine and animal foods over vegetables.”
Lifestyle factors such as obesity, tobacco use, heavy use of alcoholic drinks, and sedentary lifestyles are also potential contributors. Lack of access to testing and insurance coverage can put someone at higher risk of colorectal cancer, Goldberg added.
Although colorectal cancer is more common among younger individuals now, he said, around 75% of new diagnoses are still among those over the age of 50.
“The deployment of the resources needed to test our entire population at younger ages would be expensive and is also subject to the restricted availability of gastroenterologists to perform high volumes of screening tests, most of which will be normal,” he said.
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What Are the Symptoms of Colorectal Cancer?
While certain high-risk people should screen for colorectal cancer before the age of 45, certain symptoms might also signal a need for testing.
One of the first alarming signs of cancer is cachexia, or unintentional weight loss.
“Cancer causes the immune system to release chemicals into the blood that cause inflammation and speed up the process of fat and muscle loss,” said Liudmila Schafer, MD, FACP, an associate professor of medicine at the University of Arkansas for Medical Sciences and an oncologist specializing in gastrointestinal cancers.
Blood in the stool regardless of age can also be a symptom, Schafer said, as cancer inside the bowel weakens the lining of the gastrointestinal tract. “Pencil-like” poop is another possible symptom, as a mass in the colon may keep stool from moving through in its normal shape.
Related:How Colon Cancer Is Different in Men
Abdominal pain, nausea, and vomiting are also common symptoms of colon cancer, she added. Tumors in the colon can prevent the digestive contents from moving forward, causing the food to go back up.
Having these symptoms may not convince a healthcare provider to order a screening if you're under 45 because there's a misconception that colorectal cancer is "a disease of the elderly," according to Goldberg.
“Younger individuals with these symptoms often need to be insistent on having testing done in order to obtain a timely diagnosis," Goldberg said.
It’s also important to note that many people with colorectal cancer will not have symptoms until their disease is quite advanced, he added. This is particularly true for people who have a tumor that originates on the right side of the colon, where stool is liquid. In this case, the tumor doesn’t present symptoms of blockage until it grows large.
How Can You Reduce Colorectal Cancer Risk?
Eating a high-fiber diet that is lower in animal fats is one good step, according to Goldberg. Maintaining a lean body weight, abstaining from tobacco use, and pursuing a physically active lifestyle are also protective measures, he said.
“Choosing to participate in cancer screening testing is also a lifestyle choice that is effective at early detection of precancerous and cancerous lesions, and this often leads to curative interventions,” he said.
There are multiple ways to screen for precancerous polyps and colorectal cancer. These include colonoscopy, stool tests looking for blood (called a FIT test) or abnormal DNA associated with polyps (Cologuard), and specialized CT scans. A sigmoidoscopy, which can examine the left one-third of the colon, doesn't involve the use of anesthesia and requires less bowel preparation than a colonoscopy.
“It is possible that in the future, blood tests looking for substances shed into the bloodstream by polyps or tumors will be useful to detect both polyps and cancer,” Goldberg said. “These are currently research tools and there is intensive interest in their development.”
Read Next:Study: Colorectal Cancer Patients Diagnosed Before 50 Have Better Survival Odds
While the recommended screening age for CRC is 45, it’s a good idea to inform yourself about the high-risk factors and symptoms which may suggest that it’s wise to seek out screening regardless of your age.