Batbayar Tserendorj is preparing to run his second Chicago Marathon on Sunday, and his journey to the starting line included a battle against cancer.

"I'm feeling great," he said ahead of the big race Sunday.

"Bat," as he's known, is cancer free now, having been diagnosed in March 2023 with the illness. Radiation shrank his tumor and bought him some time, but doctors told him his best chance at survival was a liver transplant.

While waiting on the transplant list, to keep his mind and body healthy, he started running with his wife, who was already preparing for the marathon.

"I never thought about a full marathon, ever. Never in my mind until the diagnosis came," he said.

After months of preparation, the night before the 2023 race, Bat received an unexpected call.

"[In] less than 12 hours, I'm going to run the marathon, then doctors call me, 'ok Bat, it’s time. We got the organ.'"

Bat was faced with a difficult decision: Pass on the race or the transplant? Despite some initial concern from his family, he chose to run.

"The main reason, I don’t know after the transplant what kind of physical shape I'm going to be in. If I'm going to run or not, recover good or not? We don't know," said Tserendorj.

He was comforted knowing the organ would still save another life, but his decision shocked even his transplant team.

"That’s a very risky situation. Normally, we prefer the patient take the organ because you never know when another organ will be available," said Dr. Juan Carlos Caicedo, Bat's transplant surgeon at Northwestern Medicine. "He was very adamant that he wants to run a marathon. He was very convinced that he wants to do it to demonstrate to himself and his family that everything is possible if you really want it and prepare yourself for it. He trained very hard to get it."

More than 100,000 people are on the national transplant list, and 17 people die every day waiting for an organ, according to experts.

Bat is lucky. He got another call, and 19 days after the marathon, he received a successful transplant.

"Unbelievable. I am so lucky," he said.

Bat was born in Mongolia, which one of the highest rates of liver cancer in the world, as chronic infection with hepatitis B, C, and D are key factors in developing the disease, according to Northwestern.

Each year, more than 800,000 people are diagnosed with liver cancer throughout the world and it is the second leading cause of cancer deaths worldwide.

Now, Bat hopes his story proves liver transplants aren't a death sentence but a second chance at life, and he is preparing to once again hit the streets of Chicago in an effort to finish this year's marathon.