A cancer diagnosis is always unexpected. But when it strikes someone in their 20s, 30s or early 40s – with no family history, no warning signs, and no obvious reason – it feels particularly unfair. That is increasingly the reality for colorectal cancer in young adults.
The numbers behind young people developing colorectal cancer are striking enough that doctors, researchers and major cancer organizations are sounding the alarm. And it’s part of a larger trend of young people getting cancer more often.
If you are under 50, this article is for you – not to frighten you, but to make sure you have the facts. Read on to understand what you can control and know when it is time to talk to your provider.
Colorectal cancer is now the top cancer killer in adults under 50
For decades, colorectal cancer was largely considered a disease of older adults. Screening started at 50, and the conversation rarely included anyone younger. That picture has changed.
According to the American Cancer Society’s 2026 statistics, colorectal cancer is now the leading cause of cancer death in adults under 50.
This trend continues to grow. Incidence in adults aged 20 to 49 is rising roughly 3 percent per year, while rates in adults 65 and older are actually declining more than 2 percent per year.
Why is colorectal cancer rising in young adults?
One of the most unsettling aspects of this trend is that researchers do not yet have a single, clear explanation for it. It’s not simply genetics. It’s also not simply what people are eating. It is almost certainly a combination of many factors – some of which we understand, and some of which science is still working to untangle.
For most young adults who develop colorectal cancer, genetics aren’t to blame. Three of four early-onset colorectal cancer patients have no family history of colorectal cancer.
Hereditary conditions like Lynch syndrome and familial adenomatous polyposis (FAP) do increase risk. But these syndromes cannot account for the scale of the rise.
What researchers can say with growing confidence is that this is a “birth-cohort effect.” This means something shifted in the environment, lifestyle or exposures of people born after roughly 1960. A recent study found that people born in the 1990s face at least four times higher early-onset colorectal cancer risk than those born in the 1960s.
Can diet and lifestyle change colorectal cancer risk?
You have the most power over your daily habits. A growing body of research is connecting the rise in colorectal cancer in young adults to the way we eat, move and live.
Ultra-processed foods and colorectal cancer risk
A recent study followed tens of thousands of women and tracked what they ate. The results were striking. Women who ate the most ultra-processed foods – about 10 servings a day – were 45 percent more likely to develop precancerous growths in their colon. These growths, called polyps, are what doctors watch closely because they can turn into colorectal cancer over time.
What counts as ultra-processed? Think packaged chips, fast food, sugary drinks, hot dogs, frozen dinners and snack cakes. These foods are made in factories with lots of added ingredients you wouldn’t find in your own kitchen. They now make up about 53 percent of what American adults eat every day. For kids and teenagers, that number jumps to 62 percent.
What you can do – and why it’s worth it
Eating more whole, real foods is one of the best things you can do to protect your colon. That does not mean you have to eat perfectly. It just means making choices that work in your favor most of the time.
Practical ways to put this into action:
- Fill half your plate with vegetables, fruits and legumes: Fiber feeds beneficial gut bacteria and helps food move through your colon quickly.
- Choose lean proteins and limit red and processed meat: Consuming red or processed meat four or more times per week is associated with about a 20 percent higher colorectal cancer risk compared to two or fewer times per week.
- Swap sugary drinks for water: Sugary beverages in adolescence and early adulthood are associated with increased early-onset colorectal cancer risk in women.
- Move your body consistently: Physical activity lowers your colorectal cancer risk. Even moderate, regular movement like 30 minutes of walking most days makes a difference.
- Limit alcohol and avoid tobacco: Both are known to increase your risk of colorectal cancer.
You do not have to overhaul everything at once. Choose one of these habits to strengthen this month, then move onto the next. It is a genuine act of self-care – and research shows these changes compound in their protective effect over time.
When should you get screened for colorectal cancer – and what symptoms should you watch for?
Catching colorectal cancer early makes an enormous difference. Here is exactly what to do and when.
Start screening at 45, no exceptions
In 2021, the U.S. Preventive Services Task Force (USPSTF) officially lowered the recommended colorectal cancer screening age from 50 to 45 for average-risk adults.
If you are 45 or older and have not been screened, talk with your primary care provider. A colonoscopy not only screens for cancer but can remove polyps before they become cancer.
If you have a family history, talk to your provider now
If a parent, brother, sister or child has had colorectal cancer, your own risk is higher. That means you may need to start screening earlier than most people – at age 40, or 10 years before the age your relative was diagnosed, whichever comes first.
Don’t wait for your provider to bring this up. Tell them about your family history and ask if you should get screened earlier or more often.
Know the warning signs and advocate for yourself
One of the biggest problems with colorectal cancer in young adults is how long it takes to get diagnosed. Young adults with rectal cancer wait about seven months from their first symptoms to starting treatment. Why are people waiting? Symptoms in younger people are often brushed off as hemorrhoids or a sensitive stomach.
Most young adults with colorectal cancer had symptoms before they were diagnosed. Don’t ignore these warning signs:
- Blood in the stool or rectal bleeding: Do not assume it is hemorrhoids without seeing your provider.
- A change in your bathroom habits that lasts more than a few weeks: Note narrower stools, diarrhea, constipation or feeling like you cannot fully empty your bowels.
- Belly pain or cramping that does not go away
- Losing weight without trying
- Feeling very tired for no clear reason: This can be a sign of hidden bleeding in your gut.
You know your body better than anyone. If you notice these signs, make an appointment with your primary care provider.
How we can help
The rise of colorectal cancer in young adults is real and serious. But you can actively prevent it. Being someone who eats more whole foods, moves their body, gets screened on time and listens when something feels off shifts the odds in your favor.
If you are due for a colonoscopy, want to understand your risk or simply want guidance on building healthier habits, talk to your primary care provider.
Learn about the cancer care and oncology services we offer at Bon Secours.
