Dane Clark is still a lung cancer patient, but it doesn’t interfere with his daily life anymore.

“It’s about as simple as it can be. I take three pills twice a day,” he says. “I’m still on cancer treatment, but it hasn’t changed my activity levels at all.”

For someone whose daily routine include caring for animals and harvesting crops on a 1,000-acre farm, that’s saying a lot. Dane and his wife, Phyllis, raise cattle and...