Robin Roberts shares a special message in honor of her 6th 'birthday'

The "GMA" anchor celebrates the anniversary of her bone marrow transplant.

Today is my sixth “birthday.”

On this day, six years ago, I underwent a bone marrow transplant to treat Myelodysplastic Syndrome (MDS). I was blessed that my sister, Sally-Ann, was a perfect match, and her stem cells saved my life.

One hundred days passed, and I had reached a critical point in surviving MDS, five years after facing a breast cancer diagnosis. I had fought off two life-threatening illnesses. Now what?

I had a choice: let my illnesses define me and give into my difficult circumstances, or embrace my experience as a “rebirth”. I refused to look back, and only looked forward. Like many others, I chose to thrive, not just survive.

Every year on my birthday, I’m truly touched by the amazing stories of “thrivership” that viewers share with me. That’s why, this year, I’m introducing a new social initiative called #thriverthursday.

Thriver Thursday spotlights "thrivers" - people who persevere, achieve their goals and even surpass them, despite life altering circumstances. Thrivers are everyone from people who have experienced a catastrophic diagnosis or unexpected loss to those facing unemployment, divorce, or personal betrayal. These are people who -- when faced with a critical choice -- chose to thrive.

Please join in on the conversation online by tagging #thriverthursday or submitting your stories on Later this year, my production company, Rock’n Robin Productions, will release a new digital series Thriver Thursday where we will spotlight extraordinary "thrivers" we have met along the way.

Looking forward to sharing your stories.