As a homicide detective, I deal with people in bad situations all the time. But to be on the other side of that equation is very scary and tough. Still, that’s exactly where I found myself about this time last year, when I learned I had a skull base tumor called chordoma of the clivus.

I’d been experiencing really bad double vision for a couple of weeks. But I chalked it up to stress. When I finally went to the doctor, he ordered...