Doctors think improved screening is behind the decline in colorectal cancers for older adults, but there's an ominous trend for younger Americans, who are below that 50 year-old screening threshold. 

Jennifer Maxwell was 44 years old and married with two children. But suddenly she lost 30 pounds, and developed high blood pressure. Medicine made her constipated. She had digestive issues, rectal bleeding, and was uncomfortable. So she went straight to her doctor.

"I even asked her at the time, how do you know it’s not something like a tumor? And I was told, that well, the exam looks fine, you are too young," Maxwell said.

A colonoscopy revealed a mass on her rectum and several spots on her liver, stage IV rectal cancer.

"So of course it’s absolutely heartbreaking knowing that she’s 44 and a mother of two, but you have to keep going," said Dr. Kanthi Yalamanchili, gastroenterologist at Baylor Scott & White Grapevine.

Despite chemotherapy, Jennifer didn't make it. She passed away at the age of 45. And that's exactly why doctors are challenging the guideline to start screening at the age of 50.

"In my practice, we are starting to stress doing colonoscopies on younger people, younger than 50," said Yalamanchili.

As for why we're seeing this more in young people, one study suggests obesity, a sedentary lifestyle, heavy alcohol use, and tobacco use could be to blame.

Without any symptoms or family history, 50 is still the magic number to start screenings, and they're typically done once every 10 years.

But as always, talk to your doctor if you have any concerns and don't be shy to get tested earlier. It could save your life.