At the beginning, it was just a twinge, a pain on the lower left side of her abdomen. Laura Perez’s first trip to the emergency room concluded with some laxatives and a reassurance that the scans showed nothing.

After all, she was only 18.

But the pain concerned Perez enough that she persisted. After three trips to the emergency room an ultrasound finally showed the cancer.

“It was really, really scary,” Perez said

Perez was referred to The University of Kansas Cancer Center, where medical oncologist Raed Al-Rajabi, M.D., professor of medicine in the division of medical oncology at the University of Kansas Medical Center, ordered new tests.

“At first, the mass on her colon appeared to be the only problem,” Al-Rajabi said. “Then we did a laparoscopic exam using a small camera and found her cancer was far more advanced than we originally thought.”

The primary tumor had penetrated the colon wall and spread throughout her abdominal cavity. Tiny cancer cells, invisible on CT scans, coated her reproductive organs and other tissues. Perez had stage 4 metastatic colon cancer.

Younger patients, more aggressive cancer

At an age where many people are launching their adult lives, getting married, starting families and buying houses, they’re also experiencing something previously inconceivable — cancer. It’s a trend that is transcending nations, races and gender — and researchers are working to track down leads and investigate the complicated factors behind it.

Roy Jensen, M.D., vice chancellor and director of the KU Cancer Center, vividly remembers his first such patient. He was in his third year of medical school, and he saw an 18-year-old woman twice — once when she presented with a melanoma on her arm and a few months later when she had developed advanced metastatic cancer.  While the odds of survival have changed dramatically for cancer patients in the past 40 years — what killed that woman in 1983 would not kill her now — there are now so many more like her.

“It used to be that you saw one younger cancer patient in your career, and it was memorable,” Jensen said. “Now the thing that is memorable is that everyone is seeing them.”

National cancer leaders like Jensen, a former past president of the Association of American Cancer Institutes, are so concerned about the trend that they are launching studies and trying to put together a puzzle that seems to have many pieces.

“Everybody is convinced that the rate of cancers in younger people is up,” Jensen said. “But he reasons behind that are still unclear.”

A study by researchers with the American Cancer Society showed that early-onset colorectal cancer rates have increased in 27 of the 50 different countries it analyzed. Additional research shows at least 14 different types of cancer have increased among people under 50.

And while everyone is trying to solve the puzzle, it is clear that this situation is less like solving a game of Clue and more like investigating a complex international crime syndicate — there are many actors and each plays a sinister part, with some yet unknown.

One doctor who is seeing the increase in younger patients is Anup Kasi, M.D., MPH, an oncologist and associate professor of medical oncology at the KU Cancer Center, who treats many patients with gastrointestinal cancer.

“Every year in our practice, we are seeing the trend shift to more younger patients, almost on a daily basis.”

Kasi can just look at his clinic schedule and see the issue.

“Generally, everyone used to be 65 and older. Now we are seeing that about 20% of our patients are younger than 50.”

Kasi noted that colon cancer is now the No. 1 cancer-related cause of death in the 40-50 age group, when it used to be brain tumors and leukemia.

“Suddenly, we are seeing a lot more, and we don’t know why,” he said.

In addition to seeing more GI-related cancers in younger patients, Kasi also pointed out that the cancer tumors themselves seem different.

“These patients often present already at stage 4, and it seems to be more aggressive than regular colon cancer,” Kasi said.

Cathy Eng, M.D., director of the Young Adult Cancers Program at Vanderbilt University’s Ingram Cancer Center, has seen a similar trend.

“A big concern is that these patients are presenting with more advanced disease,” Eng said. “My youngest patient right now is 17. These are people who are too young to be screened,” dismissing the idea that the increase is just a reflection of increased screening.

“The trend has been there for the past decade,” she said, “But it’s rising by a little over 2% for the last year. It’s getting more attention in part because we don’t know why.”

Obesity and other culprits

Obesity is a prime suspect in all types of cancer risk, whether early-onset or otherwise. Jensen pointed out that obesity is proven to increase cancer incidence in 13 different types of cancer.

“There is a lot of speculation about the seeming rise in early-onset cancers, but obesity is proven to increase cancer risk,” Jensen said.

According to data from the Centers for Disease Control, just over 40% of adults in the United States are obese, and nearly 75% of U.S. adults are classified as overweight or obese. In addition, just over 20% of adolescents aged 12-19 are obese and 35% of adolescents are considered overweight or obese. Obesity has become a worldwide problem as one in eight people worldwide are obese, which translates to more than 1 billion people.

While obesity is a proven risk for cancer, it’s possible that the inflammatory changes brought on by excess weight and sedentary lifestyles could be associated with cancer as well.

The types of cancers that are most likely to be boosted by obesity are endometrial and esophageal cancers, but colon cancer and breast cancer are on the list as well. Also of note, a recent study following more than 2 million people in Spain found that being overweight or obese was linked to 18 different cancers, including some not yet on the commonly accepted list. Also, people who had a higher body mass index at the time of their first cancer diagnosis had higher risks of developing a second, unrelated cancer in the future.

Kasi points out that obesity and being overweight may be related to early onset cancer trends, as may sedentary lifestyles.

“There is a common theme here, and it is increased inflammation,” he said. “It could be inflammation and how all of these different exposures impact the microbiome.”

Kasi notes that studies show that cancer patients who exercise experience better results and fewer instances of additional cancer.

“It appears there is a connection between lifestyle, exercise and the immune system,” he said, explaining that the immune system can be amped up to attack cancer cells that survive treatment.

There are a few theories that stand out to Ajay Bansal, M.D., professor in the Department of Gastroenterology at KU School of Medicine and medical director of the Gastroenterology Cancers Prevention Clinic at KU Cancer Center.

“One of the biggest risk factors for colon cancer is sedentary lifestyle,” Bansal said.

He also points to the double whammy of eating ultra-processed food and eating fewer fruits and vegetables. Changes to the microbiome can all be impacted by diet, exercise, pesticide exposure and perhaps even microplastics. The solution, regardless of the specific cause — exercise.

“Exercise boosts the immune system,” Bansal said. “When we exercise it helps us stay healthy and improve our immune system as well as our overall health.”

Bansal cited a study in the United Kingdom that found patients who began exercising experienced a 37% lower chance of repeat cancers. Another study from M.D. Anderson showed that patients who rode a bicycle for 45 minutes a week had better immune cells in the colon.

“To me, the biggest take-home is that, as a society, we really need to encourage people to exercise, eat more fruits and vegetables and eat less ultra-processed foods,” Bansal said. “And it’s the food habits we’re developing between age 2 and 12 that really matter. Cancer takes time to develop. The body has amazing ability to protect itself.”

Unique challenges with early-onset cancers

When patients present with cancer earlier, they may be so young they don’t have insurance or are so busy they don’t take symptoms seriously. However, younger patients also have more to lose in a fight against cancer. Early-onset cancer patients often need to take action to preserve fertility, and that cannot be done if they are diagnosed too late.

“The young ones with colon cancer present really unique challenges,” Bansal said, noting that many of these patients are at point in their lives where they are looking to start families. “The location of the cancer can really affect successful conception, among other issues.”

Bansal said studies show that patients younger than 50 can take three times as long to get the right care and appropriate procedures.

And while younger patients who have a genetic predisposition to cancer may be able to qualify for screenings, others do not. The advent of blood tests for cancer may help, as will educating primary care physicians and pediatricians.

Bansal said that the early-onset trend is affecting those patients with a genetic predisposition to cancer as well. The most often inherited cancer disorder that increases a person’s risk for colon cancer is Lynch Syndrome, characterized by a mutation in certain genes, according to the American Cancer Society. People with Lynch syndrome also are at increased risk for numerous other cancers.

“It used to be if you were born with Lynch Syndrome, you might get cancer in your 40s, 50s or 60s. Now you might be 25,” Bansal said.

Education, not blame

If lifestyle may play a role in early onset cancer, how can doctors and researchers encourage awareness without placing blame?

“Not every patient who comes in with early-onset cancer leads a sedentary lifestyle,” Eng said, noting that one of her young patients is a champion pickleball player. “It’s important that we educate everyone without blaming anyone.”

Nikki Wood, D.O., agreed. Wood is co-director of the Surveillance for Predisposition to Tumors (SPoT) Clinic and director of the Cancer Center Biorepository at Children's Mercy Hospital. She also is a professor of pediatrics at University of Missouri-Kansas City School of Medicine.

“We have to be very cognizant of not pointing blame at any parent while also doing what we can to reduce risks and advocate for policy change,” Wood said.

Wood, who works with children who are at a high risk of cancer, also is interested in the link between cancer and environmental exposures. Wood has engaged in a variety of activities designed to educate physicians and parents on ways to avoid risk, particularly in populations that already have a genetic predisposition to cancer.

“As oncologists, we are trained to treat cancer, not prevent cancer,” Wood said, adding that educating physicians can be just as important as educating parents and patients.

“We have very good evidence now with pesticides, for example. We can assess and provide risk reduction strategies,” she said. “There are some very simple, inexpensive things you can do.”

For example, families that work in agriculture can leave shoes outside and change clothes before entering common spaces or sitting on the family couch.

“Knowledge is power, and we do have a lot of knowledge in how to decrease some of these exposures.”

As a clinician who works with children who get cancer and children who are predisposed to cancer, Wood is used to the hard questions.

“I often say, ‘We can’t identify why your child got cancer, but we do know that air pollution and pesticides can increase your risk.’”

Wood also explains to parents that survivors of childhood cancer are at more risk for chronic health conditions.

She often explains to parents that while only 15% of cancers have a known genetic cause, cancer can be something that requires the interaction of both genetic predisposition and environment.

“There is no doubt that research shows there are associations, and there is no doubt that more research needs to be done,” Wood said.

Research and prevention

Public awareness about early onset colorectal cancer has increased in recent years with several celebrities revealing they had the disease.

In February 2026, actor James Van Der Beek died at age 48, after revealing in 2024 that he’d been diagnosed with stage 3 colorectal cancer — without any glaring symptoms other than a change in bowel habits he initially found unconcerning. Van Der Beek, famous for starring in the circa-2000 television series “Dawson’s Creek,” left behind a wife and six children.

Professional baseball player Trey Mancini was 28 when anomalies in routine blood work led to a diagnosis of stage 3 colon cancer. Mancini missed his entire 2020 season with the Baltimore Orioles because of his cancer treatment, but he returned to baseball the following year and has remained cancer free.

Chadwick Boseman, known for blockbuster movie roles including “Black Panther,” kept the news private when he was diagnosed with stage 3 colon cancer in 2016. However, his family revealed the diagnosis after he died in 2020 at age 43.

Almost every cancer authority advises the same course of action: reduce known risks now but also focus on developing additional research and increasing awareness of cancer as a younger person’s disease.

“The best thing we can do is continue to bring attention and education to this pattern,” Eng said.

She reiterated that recent studies are showing this is a worldwide issue.

“The reality is that this is a real trend, not a function of more screening, and it’s not just in the United States. It’s showing up in Europe, in Asia, in Africa.”

Eng said that it is critical to educate providers to look for cancer where they may not have seen it before.

“We need to educate everyone in the community,” she said. “I hear this time and time again, ‘I went to a doctor, and they said I was too young to have cancer.’ We need everyone to learn the potential symptoms of colon cancer, which include any changes related to bowel habits and any anemia that cannot be explained.

Encouraging young cancer patients to take part in clinical trials is critical.

“We need to all be learning more and collecting as much information as possible,” she said. “We need to be capturing as much data on these young patients as we can.”

Funding is a critical component, Eng admitted.

“We need to dedicate funding to research in these populations,” she said. “If polyps are presenting in 25-year-old patients and have been developing for a five-to-10-year span, more research is needed on younger patients. We need to know what is occurring. Why are these people developing tumors at such a young age? There needs to be a larger global effort to collect data on these patients.”

Bansal agreed.

“Based on the trends we’re seeing now, it’s going to get worse before it gets better. We must do something now.”

After her diagnosis in 2017, Perez faced an aggressive treatment regimen. After four months of chemotherapy, she underwent an invasive surgery. The procedure — cytoreductive surgery followed by hypothermic intraoperative intraperitoneal chemotherapy, or CRS-HIPEC — involved a team of surgeons removing the cancerous section of Perez’s colon, removing tumors throughout the abdomen, removing reproductive organs and, finally, bathing remaining organs and tissues in a heated chemotherapy solution to destroy any hidden cancer cells. Another two months of chemotherapy followed.

Perez, who remains cancer-free, counts herself fortunate. She was on her father’s insurance when she began having symptoms, so unlike many young people who are uninsured she didn’t hesitate to go to the doctor. She encourages other young people to listen to their bodies and to take action.

“Find somebody who is really willing to listen,” she said. “Don’t ignore what your body is trying to tell you.”

Perez has been forever changed by her experience with cancer, and she wants to launch a nonprofit to benefit cancer research. She’s also pursuing a career in health care as a respiratory therapist.

“Cancer has had a big impact on my life,” she said. “I want to help other people with cancer, and I want to tell young cancer patients like me, ‘I know it’s really hard, but you will get through it. Keep fighting.’”