When I received a phone call about an abnormality discovered during my mammogram in December 2016, I didn’t think much of it. I was prone to getting fluid-filled cysts in both my breasts, and I’d always gone in and had the cysts drained. But this mammogram was different: it showed a solid tumor in my right breast.

I went in for a biopsy, and the results left me in shock. I really didn’t know how to accept my HER2-negative breast...