I am a numbers person. So, when my wife, Emily, was diagnosed with non-Hodgkin’s lymphoma in August 2013, I turned to the internet for some statistics. I quickly discovered that online research is a double-edged sword.

On the one hand, I could educate myself about my wife’s disease. I learned about things like CD19, a biomarker that can factor into the development of lymphoma. But I also saw one word used over and over again in...