Colorectal cancer is increasingly becoming a younger person’s disease, new research from the American Cancer Society shows.
Since the mid-1990s, rates of colorectal cancer—cancer that begins in the colon or rectum—have been on the rise in people younger than 55, increasing at a rate of 1% to 2% each year, according to a new report report published in March in CA: A Cancer Journal for Clinicians.
In 1995, adults under the age of 55 made up just 11% of all colorectal cancer cases; by 2019, that number had jumped to 20%, with many cases being diagnosed at a more advanced stage. This is despite colorectal cancer incidence in people over the age of 65 remaining stable over the past few years, and colorectal cancer mortality continuing to decline.
“Progress in reducing colorectal cancer incidence and mortality is now confined to adults 65 years and older and the landscape of the disease is rapidly shifting to younger patients and more advance disease and diagnosis,” first study author Rebecca Siegel, MPH, a cancer epidemiologist and senior scientific director of surveillance research at the American Cancer Society, told Health.
Though researchers are still searching for the causes behind the rising colorectal cancer rates among younger populations, the disease remains one of the most preventable types of cancers, globally.
According to Siegel, there are many opportunities to reduce your risk of colorectal cancer—from maintaining a healthy weight and staying active, to reducing your consumption of processed meats and getting screened on time. While there are still certain non-modifiable risk factors for the disease—including age, family history, and certain genetic syndromes or chronic diseases—here are six proven ways for anyone to lower their risk.
The single most effective way to lower your risk of colorectal cancer is to get screened routinely, beginning at age 45, if you’re at average risk for the disease.
The large majority of colorectal cancers begin as precancerous polyps, or abnormal growths, in the colon or rectum. Colorectal cancer screening can help effectively remove these polyps before they turn into invasive cancer, ultimately preventing the disease. Screenings can also detect cancer at earlier stages when the disease is easier to treat.
“[Screening] influences mortality both through reducing incidence and detecting cancer early, before symptoms arise and when treatment is more often successful,” Siegel said.
Colonoscopies are the most well-known method for colorectal cancer screening, but other less-invasive methods include flexible sigmoidoscopies (in which the lower third of the colon is examined, compared to the entire colon with a colonoscopy) and stool-based tests. Virtual colonoscopies may also be an option for some patients.
Depending on the type you choose, colorectal cancer screenings take place every year, every three years, every five years, or every 10 years. This continues until age 75, when people can discuss with their healthcare providers if colonoscopies are still necessary, and at what cadence.
For people with an increased risk of colorectal cancer due to inflammatory bowel disease (IBD), personal or family history, or certain genetic syndromes, screening may begin before the age of 45 and take place more often.
While you can’t change your family or personal history of colorectal cancer, knowing about the history of disease in your family can help you gauge your own personal risk.
If there have been numerous cancer diagnoses in your family—not just colorectal cancer but other types including breast cancer, uterine cancer, or prostate cancer—you may want to consider genetic testing, said Andrea Dwyer, BS, codirector of the University of Colorado Cancer Center’s Colorado Cancer Screening Program.
Further, if you have a first-degree relative (mom, dad, sibling, or children) who had colorectal cancer or a precancerous polyp, you’re at an increase risk of developing the disease as well, and may need to start getting screened up to 10 years before people at average risk.
The strong stigma surrounding not only colorectal cancer but bowel diseases in general prevents many families from openly talking about the conditions and the symptoms that accompany them, Dwyer added.
Knowing your family history—and therefore your personal risk—is critically important to getting screened on time and taking steps that can lower your risk of colorectal cancer. “Reducing that stigma has got to be central to that, so that we make bowel health, colon health, cancer talk part of what families talk about,” Dwyer said.
Red meats and processed meats—including hamburgers, hot dogs, and sausages—have consistently been linked with an increased risk of colorectal cancer—by some estimates, red meat and processed meat can increase colorectal cancer risk by 20% to 30%.
You don’t need to cut red meat out of your diet completely, but try to seek out high-quality meats and swap out the red, processed meats for leaner white meats like chicken or pork, Dwyer said.
Conversely, other evidence shows eating a diet high in natural sources of fiber (fresh fruits and vegetables, nuts and legumes, and whole grains) can help reduce one’s risk of colorectal cancer, according to Anton Bilchik, MD, PhD, a surgical oncologist and division chair of general surgery at Providence Saint John’s Health Center.
“It’s really about staying away from an exorbitant amount of fried foods and meats,” Dwyer told Health.
Cigarette smoking is well-known for its link to lung cancer, but it can cause cancer nearly anywhere in the body—including in the colon and rectum. The poison in cigarette smoke not only damages and changes cells’ DNA—which can lead to cancer—but it can also weaken the immune system, making the it more difficult for the body to kill cancer cells.
Cigarette smoking may also alter the gut microbiome, according to research conducted in mice, by impairing the gut barrier function and promoting cancer-causing and pro-inflammatory pathways in the digestive tract.
Though smoking can cause colorectal cancer in both men and women, research has shown that cigarettes can impact the location of the cancer in each sex: Women, for example, have a higher risk of right-sided colon cancer and rectal cancer from smoking than men, while men are at a higher risk of left-sided colon cancer.
Alcohol consumption also increases the risk of at least six different cancers, including colorectal cancer. Compared to no alcohol intake at all, moderate to heavy alcohol consumption is associated with a 1.2- to 1.5-fold increase in colorectal cancer risk.
It’s unclear how alcohol can affect cancer risk—it’s likely that alcohol consumption is linked to cancer risk in a few different ways. Once it’s in the body, alcohol can be converted into acetaldehyde, which has been shown to cause cancer in lab animals. Drinking alcohol can also lead to oxidative stress in cells, which can ultimately damage cells and increase the risk of cancer.
Alcohol may also effect other bodily functions that are necessary to maintain optimal health—like lessening the body’s ability to absorb folate, raising the levels of hormones in the body, and contributing to weight gain.
People with obesity are at an increased risk of numerous types of cancer—they are 1.3 times more likely to develop colorectal cancer, specifically, than people without obesity.
Though BMI (body mass index) is an imperfect measurement of health, people with a BMI of over 30—technically considered obesity—in young adulthood may also be at an increased risk of early-onset colorectal cancer, compared to those with a BMI of less than 25.
Having obesity can cause certain changes in the body which may help provide an environment for cancer to develop, including long-lasting inflammation, higher levels of insulin, insulin-like growth factor, and sex hormones.
According to Dr. Bilchik, staying at a healthy weight is widely believe to help lower your risk of various types of cancer.
Strong evidence shows that physical activity is linked to a lower risk of several types of cancer, including colorectal cancer.
Current WHO recommendations for physical activity—at least 2.5 hours of moderate-intensity or 1.25 hours high-intensity weekly—have been linked to a 7% reduction in cancer risk, primarily for breast and colorectal cancer.
Physical activity can help reduce the risk of multiple types of cancer, including colorectal cancer, potentially by inhibiting tumor growth, increasing immune function, reducing oxidative stress, and repairing damaged cells.
“Exercise is considered anti-inflammatory and also has a positive effect on the immune cells and the bacteria in our body that helps prevent the development of colon cancer,” Dr. Bilchik said.
Independent of physical activity and obesity, time spent being sedentary may also increase early-onset colorectal cancer risk: Research published in 2018 in the journal JNCI Cancer Spectrum found that women—the main focus of the study—who spent more than 14 hours per week watching TV and being sedentary were likelier to be diagnosed with colorectal cancer than those who were sedentary and watched TV for less than seven hours each week.
In addition to the anti-inflammatory effects of exercise, movement in general may help reduce the risk of colorectal cancer by speeding up motility, or moving food through the digestive system more quickly, which can reduce exposure to potential carcinogens.