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WATCH NOW: Vaccines and mammograms: In some women, one can impact the other
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WATCH NOW: Vaccines and mammograms: In some women, one can impact the other


Since the COVID-19 vaccine became available, radiologists have noticed that some women developed swollen lymph nodes that showed up on mammograms if their screenings were done shortly after vaccination.

Lymph nodes play a vital role in the body’s ability to fight off infections and the COVID-19 vaccines from Pfizer and Moderna stimulate the body’s immune system. So it would make sense that lymph nodes might swell as they go about mounting a defense against the virus.

But sometimes the small, bean-shaped size glands become enlarged because of cancer. During a mammogram, radiologists look closely at the 20 to 40 lymph nodes in a woman’s armpit to see if they’ve changed in size.

And when local specialists started seeing that after women were vaccinated, they consulted with colleagues near and far, said Dr. Roni Talukdar, medical director of the Imaging Center for Women on the campus of Mary Washington Hospital.

“As we started to put two and two together, we realized that most patients were incurring this in the same arm as their vaccination,” he said.

Vaccine can cause swollen lymph nodes, which might be confused as a rare sign of breast cancer on annual mammograms

The harmless and temporary swelling caused by the vaccine happened in a small percentage of women—one of every 10 to 15—according to national data. But that translated into significant numbers “considering how many women we see,” Talukdar said.

The discovery prompted the Society of Breast Imaging to encourage women to schedule their mammograms, either before they get vaccinated or at least four weeks after their second dose.

“This reduces the chance that swollen lymph nodes from the vaccine will appear on your mammogram,” the society stated.

But schedules don’t always conform to national guidelines, and what’s a woman to do if she’s already made an appointment for her annual mammogram—then is notified that it’s her turn to get vaccinated?

Keep both appointments, the society advises, especially if women already are overdue for mammograms because they skipped last year’s screening during the pandemic. Just be sure to tell the technologist about being vaccinated and in which arm it was given.

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“We want people to get vaccinated and to get their screening mammograms,” Talukdar said. “As you know, the only way we can return to some sense of normalcy is to get the COVID vaccine.”

The Imaging Center is recommending that women not delay, either their mammogram or the vaccine. He said radiologists will note on which side the vaccine was given and use that in the interpretation of the mammogram results to both screen for breast cancer and avoid unnecessary callbacks.

Swollen lymph nodes can occur after any vaccine, even the flu shot, but have been more evident with the COVID vaccine, said Dr. Jeffrey Weigle, medical director of the mammography program at Spotsylvania Regional Medical Center.

“Because it’s so much more prevalent and because it’s foreseeable that the majority of the population is going to get this vaccine in short order, how many women are we going to be calling back in for potentially unnecessary workups and biopsies?” he wondered.

That’s why the Spotsylvania hospital and its sister facilities operated by HCA Virginia are encouraging women to follow the Society of Breast Imaging’s guidance on the timing of shots and screenings.

But like other radiologists, he doesn’t want women to put off their annual mammograms any longer than necessary. For those who are going on two years since their last mammogram—because they canceled appointments during the pandemic, “we certainly don’t want to delay them even further,” Weigle said.

“Unfortunately, six months can mean a lot of time in breast cancer growing,” Talukdar said. “Definitely, if you’re due, come in, but if you’re overdue, even more so come in.”

Those who have enlarged lymph nodes because of the vaccine, then get mammograms which show the swelling, will have to come back for follow-up appointments, Weigle said. At such visits, radiologists may be able to do an ultrasound of the affected arm, instead of an invasive biopsy, to see if the vaccine was the cause, he said.

If a woman’s lymph nodes swell because of the vaccine, they usually return to normal on their own within a few days or weeks, according to the Society of Breast Imaging. The closer the mammogram is done to the time of the vaccine, the greater the chance of swollen lymph nodes showing up in the films—if they swell at all, radiologists said.

Being called back for more appointments can trigger anxiety and bring on additional expenses. While most insurers will pay for screening mammograms, they don’t fully cover the costs of follow-up treatments.

Talukdar stressed that the vast majority of patients who get the vaccine have no swelling at all. He doesn’t want any women to decide against getting vaccinated—or getting a mammogram—but wants them to realize the timing of the shot could have an impact on the interpretation of the screening.

“The incidence of breast cancer has been increasing .5 percent per year, but the number of people dying from it has dropped 35 percent over 30 years,” and that’s primarily because of early screening, Talukdar said. “At the end of the day, please get your vaccine and please get your mammograms.”

The Society of Breast Imaging also stressed that its guidance about swollen lymph nodes in regards to the COVID-19 vaccine does not apply to women who have other breast symptoms. Anyone with changes in their breast or underarm, such as pain or a lump, should contact their medical provider.

Cathy Dyson: 540/374-5425

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