Mammograms show swelling due to COVID-19 vaccine, radiologists say 'don't worry'

Women planning to schedule their annual mammogram might want to consider the timing of their COVID-19 vaccines.
FRESNO, Calif. (KFSN) -- Women planning to schedule their annual mammogram might want to consider the timing of their COVID-19 vaccines.

More and more doctors see a side effect. The shots often cause enlarged lymph nodes in the armpit or near the collarbone, which can be mistaken as a sign of cancer.

But if you've recently been immunized, medical experts say not to worry.

"If it's within four weeks after your vaccination, then you have a higher chance of having enlarged lymph nodes on the side where you have the vaccine," said Dr. Hannah Milch, a radiologist and assistant clinical professor at the UCLA David Geffen School of Medicine.

"If you have it in your left arm, the lymph nodes in your left armpit may be bigger than normal. This is a body's normal response. It's doing what it should do, and it will go back to back down in size," Dr. Milch added.
Enlarged lymph nodes can appear after two days of being vaccinated and last between four to 12 weeks.

"I would say once or twice a week this is coming up in my practice, so that's pretty frequent." she said.

Dr. Milch says the swelling isn't unique to the COVID-19 vaccine and is also seen in people who get the annual flu shot, "Flu vaccine season, I probably see it like twice total."

The Society of Breast Imaging recommends scheduling your mammograms before being vaccinated or four to 12 weeks after your second dose.

"That's only if it works for you. If not, just keep your screening mammogram appointment because the last thing we want to do, we definitely don't want to delay vaccination, but we don't want people to all be delaying screening either," Dr. Milch said.

Celia Garcia of Fresno knows the importance of routine mammograms well.

"It's important to get your mammogram because it could potentially save your life the way it saved mine. If I hadn't gotten it at that specific time, then there would have been a potential chance that it could have been a different level of cancer stage," Garcia said.
She was diagnosed with breast cancer in 2016 and is now in remission.

"Getting that mammogram, I was able to be, you know, be there for my small daughter, you know, my daughter is small, and for my son and for my family," Garcia said.

If you do go for a mammogram soon, you'll likely be asked about your COVID-19 vaccine status during your appointment. But if you're not, let your provider know.

"You can tell the technologist that you just had the COVID vaccination, and which arm you had it in and when. So they can document that. If somebody gets a screening mammogram and we see enlarged lymph nodes, we ask them to come back for an ultrasound usually, and we take another look," Dr. Milch said.

Dr. Milch recommends everyone keep their vaccine appointment and work with your provider to coordinate making an appointment for a mammogram.

She also cautions that routine mammograms can detect breast cancer early and that it shouldn't be delayed.

"If somebody comes in, and they have enlarged lymph nodes, let's say, on a side where they had cancer in the past. That might send off more alarm bells and if they had no history of cancer," she said.

"So we take that very seriously. Having said that, it's perfectly possible if they get a vaccination in the same arm as the side where their breast cancer was that they will have the same reaction as somebody who did not have a history of breast cancer," Dr. Milch added.
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