Colon cancer caught Diane McAdams by surprise in 2012.

The Farmerville business consultant thought she was having a heart attack, but the pain in her chest was caused by intestinal distress.

She had no family history of colon or rectal cancer and had not had a colonoscopy to screen for the disease.

“It shows up without any warning,” McAdams said.

McAdams, 55, has been cancer-free for two years this month, and now she speaks out for the Colon Cancer Alliance, encouraging others to have a colonoscopy at 50 as doctors recommend.

On Saturday, McAdams will attend Baton Rouge’s Get Your Rear in Gear 5K run and walk sponsored by the Colon Cancer Coalition. A giant, walk-through inflatable colon sponsored by the Colon Cancer Alliance and Bayer Healthcare will offer a visual aid, showing both healthy colon tissue and polyps — small clumps of cells that can become cancerous.

McAdams said that type of education may have helped her. “If I had someone who talked to me before, it would have saved a lot of heartache,” she said.

McAdams said she believes that an unhealthy diet played a role in her cancer, and she encourages her children to eat well. A lack of exercise and a fatty diet could be a factor.

“It’s no longer just an old person’s disease,” she said.

While doctors often push patients to have colonoscopies beginning at 50, McAdams said that people with a history of colon cancer in their families should have earlier screenings that start 10 years before the family member’s diagnosis. She is pushing her children to have colonoscopies at 41 — 10 years before her diagnosis at 51.