(AP Photo/Columbia Missourian, Katie Barnes)
By Tuesday, his legs hurt so badly he could barely walk. Working his construction job with Emery Sapp & Sons was out of the question. Riding horses on his grandfather's pasture in Columbia was unthinkable.
By Wednesday, the pain was so bad that his mother, Tina Bartels, took her then 16-year-old son to their pediatrician. He was referred to Children's Mercy Hospital in Kansas City where he had a magnetic resonance imaging scan on his right knee.
When the oncologist came back with the MRI results, the news made June 9, 2005, one horrible day.
Collin Bartels had cancer. Again.
"Initially, we didn't think it was cancer at all," his mother said. "He had been off of chemotherapy for five years so we thought he was cured, cancer-free. But we thought maybe this is one of the long-term side effects of the chemo."
But it wasn't a side effect of chemotherapy. It was leukemia. Again.
At age 3, Collin Bartels had been diagnosed with acute lymphocytic leukemia and went through an intense 2 1/2 years of chemotherapy. He was a cancer-free kindergartner.
Still, the doctors can't definitively say if the new development of cancer was a relapse from childhood or an entirely independent case. Whichever, the effect was still the same: Bartels began to get sick, quickly.
Just eight days after finishing his sophomore year at Rock Bridge High School, he began a summer-long treatment schedule. While his friends were enjoying the warm weather, summer sports and pools, by August, he was receiving chemotherapy. But there were complications.
Doctors had to work fast to save his life. He was given a 5 percent chance to live if he didn't have a bone marrow transplant right away.
On November 17, 2005, he received a bone marrow transplant at Children's Mercy Hospital from an overseas donor. He stayed at the hospital for 72 days.
When he had the transplant, his white blood cell count was at zero and his immune system was shutting down. He could no longer fight infection.
As a result, he was put into a sterile transplant unit.
In February of 2006, his family took him home against his doctors' orders.
"He could see his friends and family again and got better and better every day," said Billy Sapp, his grandfather. "In Kansas City, he was just blah. When he got home, every day you could see a sparkle in his eye."
By May 2006, Bartels' health was more stable. It had been about six months since the transplant and he was now eating on a more regular basis. He was keeping more normal meals down.
Bartels, who is now cancer-free, competes in horse competitions including the Missouri State High School Rodeo Championships held at the Boone County Fairgrounds.
Participants compete by trying to successfully separate two cows from a herd in the shortest amount of time.
Now able to return to horseback riding and rodeo, Bartels appreciates his time in the saddle a bit more than before.
He said going to shows is enjoyable, but it goes deeper than the competitions.
"Being out here, going out and riding on the trails, riding at home and practicing, that is what I really love."