She was a small business owner and mother in her 30s when she first noticed blood in her stool and new constipation. 

At first, she tried changing her diet. 

The problems didn’t improve, so she went to her primary care provider, who gave her advice for treating the symptoms.

Finally, she went in for a colonoscopy and received a surprising diagnosis: colon cancer.

The story illustrates how important it is for both patients and health care providers to be aware of increased rates of colorectal cancer in younger people said Christine Veenstra, M.D., M.S.H.P., who was the patient’s oncologist at the University of Michigan Health Rogel Cancer Center.

“The vast majority of times people with these symptoms do not have colorectal cancer, but it’s something we want people to be aware of,” said Veenstra, associate professor of medical oncology at Michigan Medicine.

A growing body of evidence shows the incidence of many common cancers has been increasing in Americans younger than 50 since the 1980s. 

In 2016, Rogel researchers found nearly 15% of patients diagnosed with colorectal cancer were younger than 50 and were more likely to have advanced disease. A study by the American Cancer Society found increases in diagnoses among younger people for 17 of 34 cancer types.

The rates of pancreatic, kidney and small intestinal cancers were two to three times higher among people born in 1990 than among people born in 1955. 

Mortality rates for several cancers, including uterine, testicular and colorectal cancers, also increased in younger people.

Rogel researchers are working to understand the complex factors causing these early-onset cancers — and how to not only effectively screen young people to catch these cancers earlier, but also reduce the risk.

Elena Stoffel, M.D., M.P.H., professor of gastroenterology at Michigan Medicine and director of Rogel’s Cancer Genetics Clinic, has spent her career studying cancer prevention and developing better ways to take care of people who are at increased risk for developing gastrointestinal cancers. She’s seen young patients who had symptoms for months or years before a diagnosis and either didn’t tell their primary care providers or were dismissed when they did.

“So many of my patients were told they were too young to worry about colorectal cancer,” Stoffel said. “But we all know nobody’s ever too young for cancer.”

Genetic factors

In general, a person’s risk for developing cancer tends to increase as they get older. However, some young people do develop cancer, and some people have genetic conditions associated with increased risk for cancer, Stoffel says. 

Some types of cancer are associated with hereditary cancer syndromes that are less familiar to health care providers and patients.

Stoffel says the breast cancer community has done a fantastic job of making sure patients, families and providers are aware that having a diagnosis of breast cancer at a young age or having a strong family history of breast cancer may be an indicator of a condition called Hereditary Breast and Ovarian Cancer Syndrome, associated with inherited changes in the genes BRCA1 and BRCA2.

SEE ALSO: How does exposure to ‘forever chemicals’ impact your cancer risk

But in her clinical practice, where she focuses on people with genetic susceptibility to colorectal and other cancers, she often hears patients say they wish they’d known about the possibility of genetic risk for other cancer types.

Lynch syndrome is a hereditary cancer syndrome associated with increased risk for several types of cancers, including colorectal and endometrial. It affects about one in every 279 people, Stoffel said — a similar rate as hereditary breast cancer.

“It’s incredibly important to talk to your doctor about your family history of cancer,” Stoffel said. 

“If you say, ‘Actually, there are several people in my family who have all been diagnosed with colorectal cancer,’ that should set off red flags, bells and whistles.”

Researchers are searching for other genetic factors for early-onset cancers. 

Genetic epidemiology studies have identified genome-wide risk markers for breast, colorectal and pancreatic cancer, which opens the possibility of customizing risk assessments for individual people, Stoffel says.

But genetics are only one piece of the puzzle. 

Only about one out of five young people with colorectal cancer have an identifiable genetic cause—which suggests there are likely factors other than genetics that play a role in the rise in cancers in young people, Stoffel says. 

Environmental factors

Like the United States, other developed countries around the world are seeing a rise in early-onset cancers, Stoffel says. 

For instance, her colleagues in Italy have also seen increases in colorectal cancer diagnoses in young people, specifically in the country’s north.

Data like these suggest that increased cancer rates may be connected to something that’s changed in people’s lifestyle over the past several decades.

“I think what we're seeing is that in the epidemiology of cancer, there are certain health behaviors that seem to offer some protection from developing cancer, and there are other health behaviors that seem to be risk factors,” Stoffel said.

For example, quitting smoking dramatically reduces the risk of specific types of cancer. 

Research has also linked obesity to cancer risk. 

Exercise is associated with decreased risk for several cancer types and can also improve cancer survival, Stoffel says.

Another possible factor is what we eat: Stoffel is working with colleagues in Europe to look for patterns among detailed dietary questionnaires completed by young colorectal cancer patients. 

Stoffel and her collaborators at Georgetown University are also examining the genetic signatures of colorectal cancer tumors that developed in young people to see if they can identify correlations with geographic areas where the patients live or grew up, as well as with their health habits and diet.

Justin Colacino, Ph.D., associate professor of environmental health sciences and nutritional sciences at the U-M School of Public Health, takes a multifaceted approach to investigating how environmental factors may affect cancer risk. His lab is particularly interested in how chemical exposures in utero and during childhood may increase risks of cancers, including breast and colon cancer, later in life.

“There’s still a large amount of the variation in cancer rates that we can’t explain,” Colacino said. 

“What labs like ours are trying to do is understand how what we call the ‘exposome’ — this totality of exposures — might impact risk.”

These exposures include pollutants or harmful chemicals in food, water, air, personal care products and more. 

One of Colacino’s approaches centers on the lab: exposing cells or mouse models to different pollutants, like heavy metals or pesticides, in a controlled setting and seeing how they respond. 

His lab also investigates whether certain tissues might be more susceptible to damage from pollutants, and what concentration of a chemical it takes to cause a change in cells or tissues.

But a result in the lab doesn’t necessarily correspond to the same result in a whole human. 

To address this, Colacino combines data from human population studies with the results from his lab experiments.

Michigan’s cancer and environment study

Since cancer is still relatively rare, researchers need a large number of people for an effective population study, Colacino says. 

He’s part of a multidisciplinary team conducting a statewide study of tens of thousands of Michiganders ages 18-49 to gain a clearer understanding of how the environment impacts health, particularly cancer risk.

The Michigan Cancer and Research on the Environment Study, or MI-CARES, which is funded by U-M and the National Cancer Institute, has been recruiting participants since 2022. 

MI-CARES researchers measure participants’ environmental exposures, habits such as sleep, and variables that may shape relationships between the environment and health outcomes, such as socioeconomic class and race or ethnicity. 

After years of gathering data, the researchers will compare the characteristics of MI-CARES participants who are diagnosed with cancer with those who are not.

Michigan is an ideal place for such a study because of the state’s industrial history.

“We’ve had community collaborators in Flint, Detroit and Kalamazoo that have been really concerned about the effects of legacy pollutants and current pollution,” Colacino said. 

“That’s why this study is so important. We have these communities that have been really disproportionately exposed.”

Who should be screened?

As researchers continue to unravel what’s causing early-onset cancer, what can young people do in light of the risks? 

A key action is cancer screening. 

The American Cancer Society’s recommended age for people with average risk to start colorectal cancer screening has lowered to 45. But some people at increased risk for colorectal cancer may need to start screening even earlier. 

People who have a family history of colorectal cancer should have a colonoscopy exam 10 years younger than the age of diagnosis of the youngest affected family member, Stoffel said. And those with a hereditary cancer syndrome like Lynch syndrome may need to start having colonoscopies as early as their 20s.

SEE ALSO: The New Age to Get Your Colorectal Cancer Screen

Similar guidelines recommend earlier screening for other cancers for people who have a family history of cancer. People with a history of risk-increasing behaviors like smoking may qualify for specialized screening.

Stoffel said she hopes to see people and their health care providers start talking about their risks for cancer early in life — when there’s time to do things to reduce their cancer risk.

“When everybody goes to see the doctor at any age — children, teenagers, people in their early 20s — part of that conversation should be a discussion about what we can do to keep your health good for as long as possible,” she said. 

“That discussion should integrate what we know about you, your family history, your health habits and behavior, to develop a plan for how we can take better care of you, with you invested in the process.”

Beyond individual change

While young people can make personal changes to reduce their risk of early-onset cancer (see “Steps to Reduce Your Risk” below), other helpful actions happen at the community and societal level.

Veenstra studies how a person’s support network of family and friends can benefit them both in diagnosing cancer and in ensuring people who are already diagnosed receive high quality care.

She’s found that spouses or romantic partners especially influence each other’s health behaviors.

“They remind people that they should get their colonoscopy,” she said. 

“They’re just somebody there to say, ‘Hey, you know that symptom you've been complaining about? Maybe you should talk to your doctor about that.’”

Younger people are less likely to have health insurance, which can lead to delays in diagnosis and make it difficult for them to access treatment, Veenstra says. 

People also need access to primary care doctors and cancer screenings, and time and resources to go to appointments.

“There are a lot of logistical factors, and I think a lot of areas where the health care system could do a better job of making these things accessible for people,” she said.

Reducing potentially cancer-causing exposures also requires collective action, Colacino says.

“Things like air pollution outside is really hard to deal with,” he said. 

“That’s where community members getting together, talking to their legislators and making their voices heard can make a big difference.”

He pointed to the legislative and economic actions that led to the USDA banning the use of Bisphenol A, or BPA, in baby bottles and infant formula packaging in 2012 as evidence that action can lead to change.

Colacino also said he is excited to see movement toward government policy changes — for example, strengthening regulations on air pollution — that address environmental injustice and help communities that have historically suffered from disproportionate pollution.

“I think that will have a huge impact on rates of cancer disparities and public health more broadly,” he said. “I think we're moving in the right direction in a lot of ways, but there is still a lot of work to be done.”

Steps to reduce your risk

Here are some actions individuals can take to help reduce their risk of early-onset cancer:

• Talk to your doctor about your family history of cancer and make a plan for cancer screening
• Talk to your doctor early if you have any unusual symptoms
• If you smoke, quit
• Limit alcohol consumption
• Eat a balanced diet, reducing red meat, processed meats, sugar and unrefined grains and increasing whole grains, fruits and vegetables
• Get adequate sleep
• Exercise regularly
• Wear sunscreen
• Get vaccinated for cancer-causing viruses like HPV
• Consider using air filters to decrease indoor air pollution
• If you have a well, have your water tested for pollutants and consider using a water filter

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