FRANKFORD (WPVI) -- Colon cancer used to be associated with older people.
In fact, long-standing guidelines don't call for screening until age 50 for most people.
But it's rising among younger adults - and no one knows exactly why.
Flame DeSouza was just 29 when she developed stomach cramps, constipation, and a little blood in her stool.
At first, neither she nor her doctor thought it was serious.
But when it continued, she went for a colonoscopy, and got the shocking news she had a tumor in her colon.
"It was a lot of confusion at first, a little bit of denial - not knowing where to turn," Flame recalls.
Dr. Richard Greenberg of Einstein Medical Center says cancer is the last thing most 20 or 30-year-olds think of - and so do many doctors.
"Many physicians would say - don't worry about it, it must be hemorrhoids," he notes.
But 2 recent studies by the American Cancer Society may have them thinking twice.
One shows that 1 in 7 new cases is in someone UNDER the age of 50.
Researcher Rebecca Siegel says while it's going up among Gen X and millennials, it's falling in older generations.
The other study shows deaths from colorectal cancer on the rise among younger adults.
Siegel calls it "a true and perplexing escalation in disease occurrence."
Dr. Greenberg suspects obesity, too much processed food, and unknown environmental factors caused the shift.
"All the things that we ingest or we inhale, they modify our genetic makeup," he says.
That makes it harder for our bodies to fight abnormal cells.
Over time, they can turn cancerous.
"The size of the tumor the doctor saw, he said took about 10 years," she says.
After surgery, Flame is now cancer-free and back to enjoying life with her son.
But almost a year to the day from her surgery, her grandmother also had a tumor removed.
So the family is especially careful about their diets, get yearly colonoscopies, and, they urge everyone they know to get screened.