Nov. 30, 2016 -- Three different doctors over 3 years dismissed Ashley Flynn’s complaints.

“I had blood in my stool, and each doctor pushed it off as if it were fissures or hemorrhoids or something else minor,” says Flynn, who lives outside Kansas City, KS.

But it wasn’t something minor. Flynn was only 24 when she was diagnosed in 2011 with stage 3 rectal cancer. She had surgery and chemotherapy beginning in late 2011 and has been cancer-free since August 2012.

Cases of colon and rectal cancer are on the rise in people under the age of 50, a group that’s rarely screened for them. According to a recent study, rates among younger people increased by more than 11% between 2004 and 2014.

In 2016, about 135,000 people will be diagnosed with colorectal cancer, which includes colon cancer and rectal cancer, according to the American Cancer Society. About one in seven of them will be under 50. Researchers at The University of Texas MD Anderson Cancer Center predicted last year that cases of colon cancer among people ages 20 to 34 will increase by 90% by 2030. They expect the number of rectal cancer diagnoses to more than double.

The problem appears to be particularly pronounced among certain minority groups, says Durado Brooks, MD, managing director of cancer control intervention at the American Cancer Society.

“African-Americans are about twice as likely as whites to be diagnosed before the age of 50,” Brooks says. “Young Alaska natives are diagnosed at 3 times the rate of whites. And this is not a uniquely American phenomenon. European nations and Australia are also seeing a rise.”

Although the overall number of young people with it remains small compared with older people, younger people are often diagnosed with more advanced disease that requires more aggressive treatment.

Flynn’s experience is typical for such cases in younger people, says Brooks.

“I hear often from young people with the disease that when they told their doctor they had rectal bleeding, their doctor told them, ‘You’re too young to have colorectal cancer screening,’ ” says Brooks. “That tendency for clinicians to disregard the possibility of colorectal cancer in younger people is one of the things we are working very hard to overcome.”