Colon and rectal cancer rates have declined in older adults in recent years, but researchers have uncovered an alarming trend: diagnoses in Millennials and Generation X are actually spiking, according to a new study published this week in the Journal of the National Cancer Institute. Researchers from the American Cancer Society analyzed data from more than 490,000 colorectal cancer cases in people who were 20 or older from 1974 to 2013 and found that compared to people born in 1950, people born in 1990 have double the risk of colon cancer and four times the risk of rectal cancer.
“It’s extremely rare for an incidence of a disease to increase this much,” says Andrea Cercek, MD, a gastrointestinal oncologist at Memorial Sloan Kettering Cancer Center.
Researchers aren't yet sure what's behind the rise, but they have some theories. For one, the same lifestyle factors contributing to the growing obesity epidemic are also associated with colorectal cancer. “It’s likely that some of the behaviors that contribute to obesity, like a sedentary lifestyle and poor diet, like high consumption of red and processed meat, and a low consumption of milk products, lead to [colorectal cancer]," says Rebecca Siegel, MPH, lead epidemiologist on the study. Some researchers are also exploring the connection between gut microbiome changes and cancer, but have yet to determine any direct link, says Dr. Cercek.
Meanwhile, both Siegel and Dr. Cercek say it's smart to keep an eye out for colorectal cancer symptoms. Many of them are easy to ignore or pass off as something minor—and young people are especially prone to dismissing them, says Dr. Cercek. “They think it’s not a big deal and they’re too busy working and living their lives, and they’re more likely to be diagnosed at a later stage.”
Here are the symptoms Dr. Cercek and Siegel say you shouldn't ignore:
- Blood in the stool (which can be bright red or dark)
- Bleeding from the rectum
- Abdominal cramping (that can’t be explained by a bug or something you ate)
- A change in your bowel movements – whether that’s in timing, frequency, shape of stool, or amount of stool
- Persistent constipation or diarrhea
- Unexplained weight loss
If you experience any of these symptoms for more than a week, it’s time to talk to a doctor. Do your homework before your appointment and find out if you have a family history of colorectal cancer—if you do, it may prompt your doc to screen you, says Dr. Cercek.
Siegel warns, however, that if you feel brushed off by your MD, you may need to push for further screening. “Most young people will just have some blood in their stool, and it will be diagnosed as hemorrhoids, which is the most likely thing,” she says. “But we need to raise awareness among physicians that these symptoms need to be followed up.”
Dr. Cercek agrees. “Say, ‘There’s data that colorectal cancer rates are rising in young people, and these symptoms are concerning to me. Should I get a colonoscopy?’” she suggests. Colonoscopies are used to search for polyps or other masses that can become cancerous.
You can lower your risk of colorectal cancer by eating a healthy diet with lots of fruits, vegetables, and fiber, and cutting down on red and processed meats. Milk has also been shown to help lower risk, says Siegel. Exercise and maintaining a healthy weight will also protect you.
“Know your body and know the symptoms, and live a healthy and active lifestyle,” says Siegel. “Those are the things we can do right now to help advert risk.”