I started using cigarettes in the early 1970s, when I was just 16. I smoked a pack a day for more than 35 years. I didn’t quit until my granddaughter was born in 2009. Even so, somehow I never thought I’d get lung cancer. When you’re young, you feel invincible. And later, you think it’s never going to happen to you.

I don’t think that way anymore. Because I’ve been diagnosed with stage I lung cancer three separate times since I...