When the headache started, Tabatha Conway recognized it immediately. Although it had been 20 years since she first felt that headache, she knew what it meant: her brain tumor was back.

“It’s a very specific headache,” Tabatha says. “It feels like blood pulsating towards the back of my head.” It’s a fitting description, because the tumor, called hemangioblastoma, grows from blood vessel cells in the brain.

A stubborn brain...