Anyone who has a mammogram or other cancer test right after a COVID-19 vaccine should alert doctors to prevent false alarms from a side effect.
Have a mammogram or other cancer test right after vaccination with COVID-19? Be sure to inform the doctor about the injection to avoid false alarm about a temporary side effect.
This is the advice of cancer experts and radiologists. Sometimes lymph nodes, especially in the armpits, swell after vaccinations. It is a normal immune system reaction, but it can be mistaken for cancer if it appears on a mammogram or other test.
“We need to get the message out,” said Dr. Melissa Chen, a radiologist at the MD Anderson Cancer Center in Houston, who recently had to reassure a frightened patient who sought cancer testing because of an enlarged lymph node.
A panel of experts from three cancer centers – MD Anderson, Memorial Sloan Kettering of New York and Dana-Farber of Boston – published recommendations in the journal Radiology last week on how to deal with tests complicated by the side effect.
The main message: “This should not prevent patients from receiving the vaccine,” said Chen, one of the co-authors.
The lymph nodes are part of the immune system, where white blood cells that fight infection accumulate, which are usually too small to be detected. But they can swell during illness and after other types of vaccines. And with the expected jump in COVID-19 vaccinations, doctors must “prepare to see large volumes” of imaging tests – including chest CT scans, PET scans and mammograms – that show swollen lymph nodes, according to similar recommendations in the Journal of the American College of Radiology this week.
The nodules most commonly affected are in the armpit and close to the collarbone, on the same side of the vaccination, said Chen.
The Food and Drug Administration lists the swelling along with other injection-related reactions commonly reported in studies of the Pfizer and Moderna vaccines, though not for the Johnson & Johnson vaccine.
It is not clear how often this happens. The FDA found that 16% of participants in the Moderna study reported some underarm swelling after the second dose. But if the lymph nodes are only slightly enlarged, they can appear on a medical examination without people noticing any swelling.
Consumer advice is still evolving. Where the experts agree: if you have recently been vaccinated, inform the radiologist before any examination. This will help them assess whether an enlarged lymph node is likely to be related to the vaccine and can simply be monitored, or whether it is worrying enough for a biopsy or other test.
And try to schedule an upcoming exam or other cancer-related exam before vaccination, if possible, without losing your place in the vaccine line, the Radiology panel said.
People with active cancer on one side of the body can choose vaccination on the opposite side to minimize confusion.
Don’t delay urgent exams, the radiologists point out. But there is some disagreement about non-urgent scans. The Radiology panel said it considered scheduling tests purely routine six weeks after vaccination. In contrast, Massachusetts General Hospital recommendations recommend dealing with the side effect with good communication, rather than delayed screening.
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