On the same summer day that 6-year-old Catie Hoch beat her own personal best jumping rope--100 in a row--the doctors discovered that the pain in her side was coming from a tumor on her kidney. "In that split second," her mother Gina Peca remembers, "your whole life changes. You're going along safety-proofing your house and trying to feed your kids the right food, thinking you have control over their safety, and you don't."
There was even less control over the course of the next two years as the cancer spread, through seven rounds of chemo, three operations on Catie's lungs and...