A Covid Vaccine Side Effect, Enlarged Lymph Nodes, Can Be Mistaken for Cancer
The condition is becoming more common as immunization rates increase. Experts are suggesting ways to ease patients’ fears and avoid needless testing.
Coronavirus vaccinations can cause enlarged lymph nodes in the armpit or near the collarbone, which may be mistaken for a sign of cancer.
As vaccines are rolled out across the country, doctors are seeing more and more of these swollen nodes in recently immunized people, and medical journals have begun publishing reports aimed at allaying fears and helping patients avoid needless testing for a harmless condition that will go away in a few weeks.
The swelling is a normal reaction by the immune system to the vaccine, and occurs on the same side as the arm where the shot was given. It can also occur after other vaccinations, including those for flu and the human papillomavirus (HPV). Patients may or may not notice it. But the enlarged lymph nodes show up as white blobs on mammograms and chest scans, resembling images that can indicate the spread of cancer from a tumor in the breast or elsewhere in the body.
The swelling in the armpit was a recognized side effect in the large trials of the Moderna and Pfizer-BioNTech vaccines. In Moderna’s study, 11.6 percent of patients reported swollen lymph nodes after the first dose, and 16 percent after the second dose. Pfizer-BioNTech appeared to have a lower incidence, with 0.3 percent of patients reporting it. But those figures reflect only what patients and their doctors noticed, and radiologists say that the real rate is probably higher, and that many more cases are likely to show up on imaging like mammograms, or M.R.I.s or CT scans.
Dr. Lehman said it was important for imaging centers to ask patients if they have had Covid inoculations and to record the date of the shot and the arm in which it was given.
Her clinic includes this advisory in a letter to patients whose screenings detect swelling but no other abnormalities: “The lymph nodes in your armpit area that we see on your mammogram are larger on the side where you had your recent Covid-19 vaccine. Enlarged lymph nodes are common after the Covid-19 vaccine and are your body’s normal reaction to the vaccine. However, if you feel a lump in your armpit that lasts for more than six weeks after your vaccination, you should let your health care provider know.”
But the expert panel also cautioned that nonroutine imaging, needed to help deal with an illness or other symptoms that might indicate cancer, should not be delayed. Nor should immunization.
In recently vaccinated people who have cancer and develop enlarged lymph nodes, it may be necessary to perform more tests, including a biopsy of the nodes, Dr. Lehman said.
She described one patient with a newly diagnosed breast tumor who had swollen lymph nodes on the same side, and had recently received a Covid shot in the arm on that side.
A biopsy was performed, an important step to determine whether there were malignant cells in the nodes that would then help decide a course of treatment. It was negative for cancer. The vaccine had most likely caused the swelling.
In another case, a woman who previously had cancer in her right breast had a routine mammogram that showed an enlarged lymph node in her left armpit, and no other abnormality. She’d recently received a Covid vaccination in the left arm. Doctors determined that no more tests would be needed unless the swollen nodes lasted more than six weeks.
In a man with a history of bone cancer, a chest CT scan performed as part of a follow-up found swollen lymph nodes in one armpit — on the side where he’d recently had a Covid inoculation. Nothing else was wrong and no further tests were needed. The same decision was made for similar findings in a recently vaccinated man who had a chest CT to screen for lung cancer, and in a woman with a history of melanoma.
“This could really impact a lot of people if we don’t start recording vaccination status immediately at imaging centers,” Dr. Lehman said. “I also want cancer patients to know they can get the vaccine on the opposite side or even the leg to avoid confusion.”
Source: New York Times