Rindy Comer felt nauseated all the time.

The then 35-year-old mother of two had complained to several doctors about her condition but felt she was getting nowhere. She was diagnosed with irritable bowel syndrome and given medication for depression.

Still, the nausea persisted. One physician told the Advance, North Carolina, woman she had a stomach virus but Comer was not convinced.

It wasn’t until a physician assistant suggested a colonoscopy to test for cancer that Comer discovered what really ailed her. She had stage 3 colon cancer.

“I was very persistent,” Comer said. “If I hadn’t kept pushing, I wouldn’t be here.”

Comer is one of a growing number of young adults diagnosed with colon cancer, a disease that usually affects older Americans. New research suggests that while the number of people age 50 and older with colorectal cancer has fallen, cases of this type of cancer among younger people are increasing.

In the next 15 years, more than 1 in 10 colon cancers and a quarter of all rectal cancer cases will be diagnosed in patients younger than the traditional screening age of 50, reported researchers at the University of Texas MD Anderson Cancer Center.

In a paper published recently in JAMA Surgery, the researchers projected that by 2030, the incidence of colon and rectal cancer in 20- to 34-year-olds in the U.S. will increase 90 percent and 124 percent, respectively.

Nationally, about 10 percent of colorectal cancer cases occur in adults younger than 50, according to the American Cancer Society.

What’s more, young adults continue to be diagnosed with colon cancer close to home. Data from Novant Health’s cancer registry of patient data from the greater Winston-Salem area shows 11 percent of new colorectal diagnoses in 2013 were among people between 20-49 years of age.

Dr. David Ramsay, a gastroenterologist with Digestive Health Specialists in Winston-Salem, North Carolina, said he’s seen several patients in their 30s with colorectal cancer over the past two years.

“In the past, if a younger patient had rectal bleeding, a doctor might have dismissed it as a case of hemorrhoids,” Ramsay said. “Now, if there’s any red flag like that, a patient needs to see a gastroenterologist.”

Tommy Mitchell of Mocksville, North Carolina, felt fatigued when he sought medical help. As the father of a baby girl, he chalked it up to being sleep deprived. The 31-year-old had also discovered he had anemia after trying to donate blood at work. During a visit to his doctor to discuss his low iron levels, the physician recommended a colonoscopy. Mitchell had a history of colon cancer in his family and his father had just died of the condition.

Following the test, Mitchell was diagnosed with stage 4 colon cancer.

“It was a big blow to us,” Mitchell said. “I had a family history so I knew it was possible, but I was 31.”

Colorectal cancer is the third most common cancer in the U.S. It’s also the second leading cause of cancer deaths, according to the Centers for Disease Control and Prevention. In 2014, an estimated 136,830 new cases were diagnosed with 50,310 deaths attributed to the disease.

It’s also preventable, treatable and beatable if it’s caught early through screenings for and removal of polyps before they become cancerous. The American Cancer Society says that half of all colon cancer deaths a year could be prevented if everyone older than 50 got screened.

But it is among the younger population where the incidence of the disease is growing. Analyzing data from the Surveillance, Epidemiology and End Results program at the National Cancer Institute, the Texas researchers found that the rate of colorectal cancer in patients age 20-34 increased 1.99 percent between 1975 and 2010. For patients aged 35-49, the increase was 0.41 percent.

The incidence in older patients over the same time frame showed a decline, attributable in large part to screening and consumer education. The researchers were unable to identify a cause for the increased cancer rates in the younger population but did point to factors of obesity, lack of exercise and poor diet as major risk factors.

Dr. Chris Connolley, a gastroenterologist at Gastroenterology Associates of the Piedmont in Winston-Salem, North Carolina, said the growing number of younger adults being diagnosed with colorectal cancer may be a result of heightened awareness and accessibility to colonoscopies.

Connolley said he believes patients as young as 30 should – at the very least – begin to have a conversation with their primary care doctor about their family history.

But should you be screened? Routine screening of people younger than 50 is not recommended under current guidelines unless a person has symptoms such as blood in their stool, stomach pain, unexplained weight loss or family history, Connolley said.

He added that the guidelines are adequate for now, per the findings of a study published in the New England Journal of Medicine in 2002 that found colon cancer to be uncommon among people age 40-49.

And considering that colonoscopies aren’t inexpensive, everyone doesn’t need to be tested. “The screening has to be cost-effective,” Connolley said.

He warned that colonoscopies are not without risk. The procedure usually involves some kind of sedation. For patients who don’t want a colonoscopy, an alternative called fecal immunochemical test (FIT) is used to detect blood in the stool. If the FIT test comes back positive, a colonoscopy would be recommended, Connolley said.

Ramsay added that FIT tests are not as sensitive as colonoscopies, may result in false positive readings and are not as good as colonoscopies at detecting pre-cancerous lesions.

Both Comer and Mitchell have been treated for their cancer.

Comer had surgery with about a foot of her intestine removed and underwent chemotherapy. She said she believes that doctors need to be more aware to the possibility that people in their 20s, 30s and 40s may have colon cancer and not immediately rule it out.

Mitchell also had a large section of his colon removed and is in his second course of chemotherapy. “I have good days and bad days,” he said of his continued treatment.

“Colon cancer can happen at any age,” Mitchell advised. “If you have symptoms, get yourself screened.”