Because COVID-19 vaccination may cause lymph nodes to swell, women who are due for a screening mammography should consider scheduling the study before receiving their first dose of a COVID-19 vaccine or 4 to 6 weeks after receiving their second dose.
By Robyn Roth, MD
Breast Imaging Specialist
Recently, the breast imagers at MD Anderson Cancer Center at Cooper, and at imaging centers nationwide, have seen an increase in patients who have a swollen lump under one armpit after receiving COVID-19 vaccines. Both the Pfizer and Moderna vaccines can cause lymph nodes to swell, particularly those in the armpit on the side where the shot was received. The swelling can occur a few days after the COVID-19 vaccine was received and can last a few weeks.
This condition is called unilateral axillary lymphadenopathy (LAD). Unilateral axillary LAD is usually uncommon and may have a wide range of causes, including infection and cancer. When unilateral axillary LAD is identified, cancer needs to be excluded as the cause.
The Society of Breast Imaging (SBI) recently updated their recommendations to reflect the increasing number of unilateral LAD detected. The recommendations including documenting when and in what arm the patient received the COVID-19 vaccine, performing additional studies when appropriate to exclude cancer as the cause, and considering a short term follow-up exam 4 to 12 weeks after the patient receives their second vaccine dose. If the lump is still present, further testing, including lymph node biopsy, may be recommended to determine if breast or another type of cancer is present.
All cancer experts agree that women should not postpone their normal breast cancer screening exams for an extended period of time. Cancer screenings save lives – catching cancer early at its most treatable stages. However, we are now recommending that women who are due for a screening mammography should consider scheduling the study before receiving their first dose of a COVID-19 vaccine or 4 to 6 weeks after receiving their second dose of a COVID-19 vaccine.
New lumps under the armpit should not be ignored. If you find a lump, it is important that you contact your doctor so it can be thoroughly evaluated.
As more information about the incidence and appearance of axillary lymphadenopathy following COVID-19 vaccination becomes available, it may be appropriate to change the timing of follow up tests or final assessment recommendations. Stay tuned for more updates!
For more information, check out these two resources:
- SBI Recommendations for the Management of Axillary Adenopathy in Patients with Recent COVID-19 Vaccination (PDF)
- Management of Unilateral Axillary Lymphadenopathy Detected on Breast MRI in the Era of Coronavirus Disease (COVID-19) Vaccination (PDF)
Dr. Robin Roth is Women’s Imaging Fellowship Director, Department of Radiology
Cooper University Health Care/ MD Anderson Cancer Center at Cooper and
Assistant Professor, Cooper Medical School of Rowan University.