Pfizer And Moderna mRNA Jabs Presenting As Breast Cancer

forbes |  Minor reactions following Covid-19 vaccination are common, and can include fever, chills, fatigue, body aches, a bump or redness at the injection site, or lymph node swelling. All of these are signs that the immune system is appropriately responding by developing antibodies. This is a good thing (although do not fear if you have no reaction at all— this is also fine). These reactions are more commonly seen in younger individuals, and because lymph node swelling tends to develop as a reaction to a nearby area of the body, the nodes in the armpit region can become inflamed after the Covid-19 vaccine. As these lymph nodes are near the outer breast tissue, women have raised valid concerns that these lymph nodes are breast masses or breast cancer metastases.

As one in eight women will develop breast cancer in her lifetime, this is an important distinction to address. Because as common as breast cancer is, inflamed lymph nodes due to breast cancer are very rare, and cause for more concern. Less than 0.5% of patients with breast cancer present with axillary (armpit) lymph nodes, but when they are present in the setting of cancer, there is a 50% chance that they are either cancerous or representing another type of cancer such as leukemia or lymphoma. This finding has led many women to seek early evaluation, including surgical consultations and mammography or ultrasonography to assess these lymph nodes following their Covid-19 vaccine. 

Axillary lymph node swelling was seen in both men and women during both the Pfizer and Moderna Covid-19 vaccine trials. The Moderna trial reported approximately 6% of patients after the first dose and about 8% after the second dose with temporary axillary lymph node swelling. The overwhelming majority of these swellings did not require pain medications or medical assessment, and most lasted no more than three days. Trial participants under age 64 developed axillary lymph nodes twice as often as those ages 65 years and older. The Covid-19 vaccine is not the first vaccination to present with axillary lymph node swelling. This has also been reported after the flu vaccine, hepatitis vaccines, polio vaccine, and the tetanus vaccine, to name a few. These similarly lead to local, temporary reactions to the body’s immune response.

In the January 2021 issue of Clinical Imaging, the authors discuss four cases of women presenting with axillary lymph nodes following Covid-19 vaccination, under the same arm as the injection site. The recommendation in their article is to repeat imaging several weeks after this finding, instead of heading to more aggressive interventions such as magnetic resonance imaging (MRI) or biopsy. Dr. Sunny Mitchell, Medical Director of Breast and Women’s Services and Director of Breast Surgery at Montefiore Nyack Hospital in New York commented, “We are seeing unilateral axillary adenopathy on breast imaging, [such as] Mammogram, Ultrasound, and Breast MRI after Covid-19 vaccinations are administered. This is presenting in individuals with a history of breast cancer as well as no history of breast cancer. Breast Radiologists are considering short term follow-up/repeat imaging prior to recommending a biopsy in these situations.”