The former "Good Morning America" co-host said she decided to announce the news because she had spent her life "sharing my joys and my disappointments with all of you: my pregnancies, my relationships, my career… I have shared my journey. So it certainly didn’t feel right keeping this part of my journey a secret."
Lunden also said she has already begun chemotherapy and hopes to inspire others to be more aware of their health.
Click here to read the full blog entry at Lunden's website.
Click here to follow Daily Voice Greenwich and receive free news updates.