The diagnosis happened after Nickles did a story for Channel 2 in October, in which she had a mammogram to show viewers how easy the procedure is.
Nickles explained to viewers what happened next:
"We shot the whole story and they took a second look at one little area, but I've had dense tissue looked at a second time before and I thought, 'Okay, no big deal.' Well, then they said, 'You have to come back in for an ultrasound.'... and I was busy, busy. I thought, 'Oh, it's just another one of those dense spots ... no big deal.' Well, then I get a phone call saying, "Hey, we really need you to come back in.' And then I got another call that said, 'Hey, I really need you to come back in.' "
A biopsy found malignant cancer cells, which would have not have shown up on a mammogram just a year before, Nickles reported.
After the lumpectomy, doctors also checked Nickles' lymph nodes, in case the cancer had spread. Those results were negative.
All the same, Nickles told viewers she will undergo radiation and chemotherapy for the next few months, to ensure the cancer doesn't return. She plans to schedule her medical treatments so they won't interfere with her TV schedule, but that will depend on how well her body handles radiation and chemo.
She also has started a blog, maryscancerstory.blogspot.com, to keep viewers informed of her progress.
Jennifer Dahl, news director at KUTV and Nickles' boss, said the anchor wrestled with the decision to go public about her diagnosis. One factor, Dahl said, is that viewers might notice the effects of radiation and chemotherapy.
"We don't know if she will lose her hair," Dahl said. "We had to disclose to the public."
Nickles, Dahl said, "is a bit of a public figure. [She's] on TV every day, and in everybody's living room."
"I don't like being the story," Nickles told the Tribune this afternoon. "The hardest part for me is not to be emotional on the air. I'm a really ugly crier."
For Nickles, going public is the right thing to do journalistically: "This started as a story, and now it's a more powerful story. This is why you want people to get mammograms."
Nickles said she is confident she will overcome cancer.
"It doesn't scare me so much, because I've met so many people who have done so well," she said. "I really do feel like I am going to kick its butt."