Couric penned a lengthy essay on her website, where she opened up about her diagnosis. Titled "Why NOT Me?", she talked about filming her getting a routine mammogram and how the day changed when, after a couple tests, her doctor abruptly asked the cameras to stop rolling as she discovered something in the scans that needed further evaluation. A biopsy later revealed it was cancer.

"I felt sick and the room started to spin," she recalled. "I was in the middle of an open office, so I walked to a corner and spoke quietly, my mouth unable to keep up with the questions swirling in my head."

Couric has experienced loved ones battling cancer, the feelings of which came rushing back when she learned she too is now dealing with the disease. Her first husband, Jay Monahan, was diagnosed with colon cancer when he was 41 before passing away in 1998. She also lost her sister, Emily, to pancreatic cancer, and her mother-in-law Carol to ovarian cancer. Both her mother and father, as well as current husband John Molner, have also battled various forms of the disease over the years.

"My mood quickly shifted from disbelief to resignation," she said. "Given my family's history of cancer, why would I be spared? My reaction went from 'Why me?' to 'Why not me?'"

Couric underwent a lumpectomy in July to remove a 2.5 centimeter tumor that was diagnosed as 1A. After being told she didn't need chemotherapy, she began radiation treatment on September 7 to eliminate "any microscopic cells that could be problematic down the line." She completed her last round of radiation on Tuesday (September 27), revealing that she is feeling fine.

Reflecting on her own cancer journey, Couric revealed she chose to share this moment in her life to serve as a teaching moment to other women who may put off getting the annual screening.

"Please get your annual mammogram," she said. "I was six months late this time. I shudder to think what might have happened if I had put it off longer. But just as importantly, please find out if you need additional screening."