AURORA, Colo. -- At first, Nick Brant, a former University of Denver soccer player, thought his stomach pains were nothing to worry about.
"Probably I should have gone to the doctor earlier, but with my family's background with stomachaches, I just thought it was a food allergy," said Brant.
When the pain lasted for a full week, tough, he went to the emergency room, and eventually tests showed a stage-three tumor in his large intestine.
"I never thought it would be me with colon cancer at 25-years-old," said Brant. "They just thought it might be colitis or irritable bowel syndrome."
Colorectal cancer is the second leading cause of cancer-related deaths in the United States (after lung cancer), and while overall rates have been declining a study released this week shows a sharp increase nationally in the GenXers and millennials with the disease.
"Almost every single patient will tell you, 'I was told I was too young to have colon cancer,' so that paradigm is starting to shift." said Dr. Christopher Lieu, a gastrointestinal medical oncologist at the University of Colorado Hospital.
He has been researching the rise of colorectal cancer in young Coloradans, and said it follows the national trend of two to three percent per year.
Because routine screening is generally not recommended for most people under 50, these cancers are often found in more advanced stages, too.
Lieu said primary care doctors should be aware of the changing statistics of the cancer.
"If these rates continue, by 2030 in the 20- to 35-year-old age group, the rate of colorectal cancer is expected to double," said Lieu. "It is still rare, but if they're aware of it, then they won't ignore it."
Doctors can't explain why the increase is happening, though obesity, poor diet, environment and medications may play a role.
"We know the answer is more complex than being obese and having a poor diet," said Lieu. "What you're seeing with patients like Nick, especially, these are fit, healthy patients that don't really have any significant risk factors to develop the disease."
Brant had a foot of his colon removed and six months of chemo.
He now has a good prognosis and hopes to raise awareness -- his siblings got colonscopies after his diagnosis.
"My brother actually had a pre-cancerous polyp that they removed, so who knows what that might have been like in a couple of years," said Brant.
The American Cancer Society is currently reviewing colorectal cancer screening guidelines.