Vaccination against coronavirus can cause enlarged lymph nodes in the armpit or close to the clavicle, which can be mistaken for a sign of cancer.
As vaccines are launched across the country, doctors are seeing more and more of these swollen nodules in recently immunized people, and medical journals have started publishing reports to allay fears and help patients avoid unnecessary testing for a harmless condition that will disappear in a few weeks.
The swelling is a normal immune system reaction to the vaccine and occurs on the same side of the arm where the injection was given. It can also occur after other vaccinations, including those from influenza and human papillomavirus (HPV). Patients may or may not notice. But enlarged lymph nodes appear as white blisters on mammograms and chest scans, resembling images that may indicate the spread of cancer from a tumor in the breast or anywhere on the body.
“I am particularly eager to get the word out to all patients under surveillance after successful previous cancer treatment,” said Dr. Constance D. Lehman, author of two journal articles on the problem and head of imaging studies at the breast at Massachusetts General Hospital. “I can’t imagine the anxiety of taking the exam and hearing, ‘We found a big lump. We don’t think it’s cancer, but we can’t say ‘or worse,’ We think it might be cancer ‘”.
Swelling in the armpit was a side effect recognized in the major tests of the Moderna and Pfizer-BioNTech vaccines. In the Moderna 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 this. But those numbers reflect only what patients and their doctors noticed, and radiologists say the real rate is likely to be higher and that many more cases are likely to appear on images like mammograms, MRIs or CT scans.
The condition was not listed among the side effects reported in a Food and Drug Administration information document on the Johnson & Johnson Covid vaccine. On Saturday, the agency authorized the company’s vaccine for emergency use.
Lehman said it is important for imaging centers to ask patients if they were inoculated with Covid and record the date of the injection and the arm it was given to.
Your clinic includes this warning in a letter to patients whose tests detect swelling, but no other abnormalities: “The lymph nodes in the armpit area that we see on your mammogram are larger on the side where you received the 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 more than six weeks after vaccination, you should inform your doctor. “
One way for people to avoid the problem would be to postpone routine mammograms and other imaging tests for at least six weeks after the last dose of the vaccine, according to an article by a panel of experts in the journal Radiology, published on Wednesday.
A professional group, the Society of Breast Imaging, offers similar advice: “If possible, and when this does not unduly delay care, consider scheduling screening tests before the first dose of a Covid-19 vaccination or 4-6 weeks after the second dose of a vaccine against Covid-19. “
But the panel of experts also warned that non-routine images, needed to help deal with a disease or other symptoms that could indicate cancer, should not be delayed. Nor should immunization.
People with cancer are generally advised to be vaccinated against the coronavirus, mainly because they are at greater risk of dying from Covid than the general population. But some cancer treatments can interfere with the body’s ability to respond fully to the vaccine, and the American Cancer Society advises patients to consult their oncologists about vaccination.
In recently vaccinated people who have cancer and have developed enlarged lymph nodes, further testing, including a biopsy of the lymph nodes, may be needed, Lehman said.
She described a patient with a newly diagnosed breast tumor who had swollen lymph nodes on the same side and recently received a Covid injection in the arm on that side.
A biopsy was performed, an important step in determining whether there were any malignant cells in the nodules that would help decide the course of treatment. It was negative for cancer. The vaccine probably caused the swelling.
In another case, a woman who already had cancer of the right breast underwent a routine mammogram that showed an enlarged lymph node in the left armpit and no other abnormalities. She had recently received a Covid vaccination on her left arm. Doctors determined that further testing would not be necessary unless the swollen nodules 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 an armpit – on the side where he had recently received an inoculation from Covid. Nothing else was wrong and no further tests were needed. The same decision was made for similar results in a recently vaccinated man who had a chest CT scan for lung cancer and a woman with a history of melanoma.
For patients undergoing breast cancer treatment, Lehman said, Covid’s injection should be applied to the arm on the other side. The vaccine can also be injected into the thigh to avoid problems with swollen lymph nodes.
“It could really impact many people if we don’t start recording vaccination status right away at imaging centers,” said Lehman. “I also want cancer patients to know that they can get the vaccine on the opposite side or even on the leg to avoid confusion.”