When I was undergoing radiation therapy for my spinal tumor, I took my 12-year-old brother to the MD Anderson Proton Therapy Center. He wanted to see the machine and was fascinated by the process.

On the drive home, he asked me, “Bubba, what’s the scariest thing you’ve ever done?”

I had to be honest with him: I told him it was the surgery I’d just gone through and proton therapy. It was really fear of the unknown. With cancer...