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Published on April 27, 2021

Sarah Siemonsma

What You Need to Know About Mammography and the COVID-19 Vaccine

With the year we’ve just lived through, you may have decided to postpone some of your yearly screenings due to COVID-19. Now that vaccines are available, more people are scheduling those screenings in the hopes of getting back to normal.

New data has emerged showing that the COVID-19 vaccine can enlarge certain lymph nodes that will show on a routine mammogram. That is what happened to Sarah Siemonsma.

Siemonsma is no stranger to breast cancer. Several of her family members have been diagnosed with the disease, making Siemonsma at a higher risk for breast cancer herself. For the last nine years, she has been a part of the high-risk breast clinic at the Avera Cancer Institute in Sioux Falls. She began her mammography screenings at 25 and continues to go every six months.

So, you can imagine that when the radiologist discussed an abnormal area on her mammogram at her most recent screening in January, she was worried.

Siemonsma had her second dose of the COVID-19 vaccine on Jan. 8. Her mammogram was on Jan. 27.

“I was probably one of the first, if not the first patient at Avera to have a screening issue because of the vaccine. I didn’t even think that could be a cause,” she said.

Siemonsma’s images showed enlarged lymph nodes under the arm where she’d received her vaccine, and the contrast was striking. It also correlated with her second vaccine shot. It was in her left arm and that’s where the troublesome lymph node appeared.

New Data in Mammography

New data is showing that up to 11% of women, or roughly one in 10, who receive the COVID-19 vaccine have enlarged lymph nodes under the arm where they received that vaccine, which is an immune response, said Michelle Bryan, MD, breast surgeon with Avera Medical Group Comprehensive Breast Care in Sioux Falls.

“You really shouldn’t see lymph nodes on a mammogram image, so this in the absence of the vaccine would be worrisome to us,” she said.

The timing of your mammogram can help. Enlarged lymph nodes after a COVID-19 vaccination can be expected for up to six weeks. Bryan assures that this is a normal response.

“Your immune system is doing what it’s supposed to do,” she said. These lymph nodes drain both the arm where the vaccine is administered and the breast. A reaction in either the arm or the breast can cause them to enlarge.

It’s recommended that if a patient can wait six weeks to have a mammogram after they’ve received their vaccine, they should do so.

“Getting a call-back is scary. And we’re just trying to avoid that for patients,” Bryan said. She said that while waiting make sense, everyone should get vaccinated and find a place where they can.

Advice: What Should You Do?

Siemonsma has this advice: Don’t panic.

She says:

  • Follow what the doctors tell you.
  • If you have your mammogram appointment scheduled, get your vaccine afterward.
  • Most importantly, don’t cancel your mammogram screening, but delay it if you have recently had the vaccine.

Fortunately for Siemonsma, when she returned for an ultrasound six weeks after her initial screening, she was fine.

And most issues can wait six weeks on a mammogram.

“The only time we are telling people that they need to actively come in for their imaging is if we’re actively working something up,” Bryan said. For example, if they had a lump or abnormal mammogram that’s currently being investigated.

The most important thing is to catch breast cancer early.

“I want it to be an easy conversation versus the more difficult one,” Bryan said. “And, really, the best tool we have for that is a mammogram.”

Learn more about breast cancer screening resources or schedule your mammogram.

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