We all know what it’s like to get hit by the flu. The muscle aches and fever make us want to stay in bed for a few days until we recuperate. However, for those who are fighting cancer, the flu can lead to far more serious complications.

It was 2005, and 47-year-old Rick Crowley had a lump growing in his neck. The first biopsy indicated that it was benign, but his doctors in Olean, New York, were not convinced. A good thing, too: The second biopsy found cancer.

I tried to ignore the pain and the feeling of being “off.” But one day, after struggling through a few minutes of yet another bad run, I stopped in mid-stride, pulled out my phone, and called my doctor.