Until November 2018, I’d never been hospitalized before. So, the suddenness of my lung cancer diagnosis at age 65 that year caught me completely off-guard.

I’d had a persistent cough for several months. But I felt it was allergy- or acid reflux-related, so I wasn’t overly concerned. Then I started having trouble climbing the stairs in my Dallas home. I didn’t have much energy, and I was losing weight. The rapid decline in my health...