Transcript for Young Cancer Warriors Ring Bell to End Their Treatment
Finally tonight here, our persons of the week. So many of us know a loved one who has been tested with their health. But rarely does a test come this early. Tonight, our very little, and inspiring, persons of the week. It's a big day for baby wren, right there in her dad's arms. Walking into that room and right up to that symbolic bell. Which signals she has completed her chemotherapy. They cheer her on, and those cheers being echoed across the country. So many hospitals do this when a child finishes treatment. We want every child to be cured and every time that bell rings, it's like, you know what, somebody else has done it. Reporter: So many of the doctors and nurses capturing the moments themselves, documenting the bells, the smiles. The triumphs. After 844 days of treatment. It's an honor. It's something that you don't take lightly. Reporter: 4-year-old Nolan enduring two years of aggressive chemotherapy. And just look at his victory lap. That bell at Texas childrens hospital waiting. And at golisano children's hospital in Rochester, New York, Zoe, a 14-year-old leukemia patient. And the surprise serenade. ??? We throw our hands up in the air today saying Ayo no no more chemo ??? Reporter: Then, it was her turn to ring that bell. I'm just so happy today because I know that I finished it and I beat it and I'm a warrior. And I'm a survivor. And just look at the picture Zoe sent us. And so we choose all of the young survivors thriving tonight. Keep ringing those bells. Thanks for watching tonight. I'm David Muir. I hope to see you right back here Monday night. Good night.
This transcript has been automatically generated and may not be 100% accurate.