A side effect of the vaccine can mimic signs of breast cancer, according to doctors.
Health experts nationwide, including a prominent Utah doctor, are warning women who get the COVID-19 vaccine to wait at least a month before getting a routine mammogram — because of a side effect of the vaccine that mimics a condition often seen in cancer diagnoses.
“We don’t want patients to get these false positives, to have this sort of alarm,” said Dr. Brett Parkinson, medical director of Intermountain Healthcare’s Breast Care Center.
Parkinson said the center’s doctors, as well as physicians across the nation, have noticed that some people who get the COVID-19 vaccine have had the side effect of swollen lymph nodes in the axilla, or the armpit area. In itself, such swelling isn’t serious, and it usually subsides within four weeks.
“Their body is mounting an immune response, and that’s a good thing,” Parkinson said.
However, when such swelling in the lymph nodes in the armpit shows up during a routine mammogram, Parkinson said, a doctor likely would call a patient back in for a more detailed examination. Such swelling, he said, can be a sign of metastatic breast cancer — a cancer that has spread beyond the breast — or lymphoma or leukemia.
The side effect shows up in 11% of patients after the first dose of the Moderna version of the COVID-19 vaccine, and 16% of the time after the second dose, Parkinson said. He added that experts expect similar findings with patients who get the Pfizer version.
“We started to look this and we realized if we don’t do something, that we’re going to have a lot of patients needlessly coming back [to their doctor] for these enlarged lymph nodes,” Parkinson said.
Parkinson said signs have been put up at Intermountain’s Breast Care Center in Murray, and other Intermountain locations that perform mammograms, telling patients that — barring other symptoms, like a lump in their breast — they should delay getting a mammogram until four weeks after getting their last dose of the COVID-19 vaccine.
(For now, the last dose is the second dose of the Pfizer or Moderna versions. When the single-shot Johnson & Johnson vaccine comes on line, as is expected after federal approval later this month, the first dose will also be the last dose, Parkinson noted.)
Parkinson stressed that if a patient has other symptoms of breast cancer — a lump in the breast, or bloody discharge from the nipple, or scaling around the nipple — they should not hesitate to see their doctor. “We will go ahead and do the mammogram,” Parkinson said.
When the mammogram is routine, as with an annual checkup, or a follow-up exam after a lumpectomy, the test can be delayed, but not indefinitely, Parkinson said.
“Do not skip your yearly screening mammogram,” Parkinson said. “Postponing it by a month or two will not be that impactful. Postponing it by a year really could be.”
Women with an average risk of breast cancer should get a screening mammogram at age 40, and every year after that as long as they are healthy, Parkinson said. Women who have a history of breast cancer in their family, such as a mother or sister, should start getting mammograms at age 40 or 10 years before the age their relative was diagnosed, whichever comes first, he said.
Parkinson said the Breast Care Center doesn’t give screening mammograms to men, who make up less than 1% of all breast cancer cases. If a man finds a palpable lump, though, he should get a diagnostic mammogram, Parkinson said.