Her blood work is normal. She has no new symptoms. For those reasons and others, doctors are hopeful that Wednesday's biopsy will result in little more than a tweaking of her treatment.
Nonetheless it is prompting concern for Chicago's first family.
"Maggie handled this well. I'm not good dealing with sickness but she can handle this well," said Mayor Daley.
Admiration and awe. Two words to describe how Chicago Mayor Richard Daley views his wife's seven year battle with breast cancer.
On Wednesday, the two were back at Northwestern Memorial Hospital. A routine MRI revealed what doctors describe as a "subtle change" in a bone lesion. They performed a biopsy to see if a change in the cancer will require a change in her treatment.
"When you go in the hospital my wife always says you think you're sick until you see someone else really sick. Put things into perspective," said Mayor Daley.
When Mrs. Daley was first diagnosed with breast cancer in 2002 it had already spread to other parts of her body.
In 2006, surgeons removed a tumor in her right breast.
Mrs. Daley's doctor says he's not overly concerned right now but depending on the biopsy results Chicago's first lady may have to undergo chemotherapy.
"She's fortunate to have the type of breast cancer where we have a number of difference strategies that can be used to maintain a phenomenal quality of life," said Dr. Steven Rosen, Maggie Daley's oncologist.
Mrs. Daley has been symptom-free for some time. While she rarely speaks publicly about her struggle, she has in the past marveled at modern medicine's ability to treat cancer like her own.
"I'm an optimist. If you asked me seven years ago 'would she be doing as healthy and doing as well today?' I probably would have said 'no.' Right now she's still doing beautifully," said Dr. Rosen.
Just hours after leaving the hospital, Mayor Daley talked with ABC 7 political reporter Charles Thomas about his wife's seven year struggle.
"She's been very fortunate for many years as a survivor. It's really amazing. She reaches out to others will illnesses, writes notes, gives them strength. It's very important," said Mayor Daley.
Mrs. Daley's biopsy results are expected back in about a week. That's when doctors will re-evaluate her treatment.