Key Takeaways

  • When women undergo breast imaging shortly after receiving a COVID-19 vaccine in the arm, their tests may show swollen lymph nodes in the armpit area.
  • Radiologists at Massachusetts General Hospital say that this is usually a normal finding, and if there are no other concerns, no additional imaging tests are needed unless the lymph nodes remain swollen for more than six weeks after vaccination.
  • The team has published an approach to help avoid delays in both vaccinations and breast cancer screening.

In addition to avoiding delays in vaccinations and breast cancer diagnoses, we hope that our model will reduce patient anxiety, health care provider burden, and costs of unnecessary evaluations of enlarged lymph nodes after vaccinations.

Constance Lehman, MD, PhD
Director of Breast Imaging, Massachusetts General Hospital

BOSTON – Swelling of lymph nodes in the armpit area is a normal response to COVID-19 vaccinations, but when they are seen on mammograms, they can be mistaken for nodes that are swollen because of cancer. In some cases, the nodes are biopsied to confirm they are not cancer. To avoid confusion by patients and their providers, and to avoid delays in either vaccinations or recommended mammograms through the pandemic, radiologists at Massachusetts General Hospital have published an approach to manage what is expected to be a fairly common occurrence as vaccination programs ramp up. The approach is described in the American Journal of Roentgenology.

“We had started to see more patients in our breast imaging clinic with enlarged lymph nodes on mammography, ultrasound, and magnetic resonance imaging. And we noticed they were coming to our clinic after a recent COVID-19 vaccination,” explains lead author Constance Lehman, MD, PhD, director of Breast Imaging and co-director of the Avon Comprehensive Breast Evaluation Center at Mass General. “We talked with our colleagues in primary care and in our breast cancer specialty clinics and realized we needed a clear plan for management.”

The team’s goals were to develop a program that supported patients to continue to engage in vaccination programs while also ensuring that patients continued to receive their routine health care needs, such as breast cancer screening. It was also important to reassure patients that swollen lymph nodes in the armpit is a normal and expected finding after vaccination.

The group’s approach is based on three principles: 1) encouraging COVID-19 vaccination; 2) reducing and/or eliminating delays, cancellations, and rescheduling of breast imaging exams; and 3) reducing unnecessary additional imaging and/or biopsies of lymph nodes that have become swollen from recent vaccination.

“In addition to avoiding delays in vaccinations and breast cancer diagnoses, we hope that our model will reduce patient anxiety, health care provider burden, and costs of unnecessary evaluations of enlarged lymph nodes after vaccinations,” says Lehman.

Lehman and her colleagues—including co-authors Leslie Lamb, MD, MSc, and Helen Anne D’Alessandro, MD—stress that no additional imaging tests are needed for swollen lymph nodes after recent vaccinations unless the swelling persists or if the patient has other health issues. This message should be communicated to both imaging staff and patients. Patient letters may read: “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.”

Lehman notes that drastic declines in screening mammography and breast cancer diagnoses are well documented across multiple health care institutions due to the COVID-19 pandemic. “This disruption of breast cancer screening is likely to result in a significant increase in cancers diagnosed at late stages and an increased demand for cancer screening procedures as delayed tests are rescheduled,” she says. “We believe our model can avoid reducing or delaying vaccinations and avoid further reduced or delayed breast cancer diagnoses based on confusion amongst patients and/or their providers.”

About the Massachusetts General Hospital

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In August 2020, Mass General was named #6 in the U.S. News & World Report list of "America’s Best Hospitals."