RENO, NV - Ophelia Wilson is a math teacher at a local middle school, she's also a marathon runner, wife and mom. You probably think she'd be the last person to get colon cancer.

“She did everything right. She's doing everything right. Extremely healthy person, eats right, exercises,” says Dr. William Pfau, Ophelia’s gastroenterologist.

For years she says she ignored the stomach problems but after a particular marathon, she decided to have it checked out.

“She said it sounds like either Crohns Disease or cancer, the gastroenterologist said its either Crohns, celiac or cancer it’s probably one of those three, says Ophelia.

Turns out both doctors were right. It was colon cancer. One that had grown outside the colon, radiation and chemotherapy followed the surgery.

“I was feeling like wow, I think I got off kind of lucky for everything,” says Ophelia.

That's because colon cancer kills 50,000 people a year, half of them men, the other half women. But if screening took place as recommended, that death rate could be cut in half.

That screening is called a colonoscopy where doctors use a flexible tube to check out the inside of a sedated patient's colon. It is recommended when patients turn 50. If polyps are found they can be removed and a cancer will not develop. If the screening is clear, patients don't have to come back for ten years.