When Althea Harry, from Freeport, started going to the bathroom more often, she scheduled a colonoscopy.

"That colonoscopy came out that I had cancer. Now that was devastating," she said.

The National Cancer Institute estimates there are 155,000 cases of colorectal cancer in the U.S. each year.

Doctors at Mount Sinai South Nassau say cases for people younger than 65 are increasing.

"We really believe that this is environmental and it probably all comes down to the food in the United States. A lot of processed food, a lot of nitrates," said Dr. Frank Caliendo, with Mount Sinai South Nassau.

Experts say pre-cancerous polyps can be caught during colonoscopies and are urging the public to get checked early and often.

"Small polyps are easily removed with these little lassos that we burn out those polyps, and now there's even more technology where we can take out even bigger polyps," said Dr. Caliendo.

Doctors say the recommended age for colonoscopies is 45 and older, unless you have a family history of colorectal cancer. If you're presenting any symptoms, then you should get checked regardless of age.

"Abdominal pain, change of bowel habits, rectal bleeding, then we do the colonoscopy at any age," said Dr. Caliendo.

Now cancer-free, Althea Harry says she's grateful for her early diagnoses and doctor.