key: cord-0768109-vfwa20t9
authors: Wolfson, Stacey; Kim, Eric; Plaunova, Anastasia; Bukhman, Rita; Sarmiento, Ruth D.; Samreen, Naziya; Awal, Divya; Sheth, Monica M.; Toth, Hildegard B.; Moy, Linda; Reig, Beatriu
title: Axillary Adenopathy after COVID-19 Vaccine: No Reason to Delay Screening Mammogram
date: 2022-02-08
journal: Radiology
DOI: 10.1148/radiol.213227
sha: de1c50d9fc86018696290dac19293717d03bc4b5
doc_id: 768109
cord_uid: vfwa20t9

Screening mammography should not be delayed after COVID-19 vaccination because axillary adenopathy is a common imaging finding and persists for as long as 43 weeks.

Unilateral lymphadenopathy, a side effect of the COVID-19 vaccines, has posed a diagnostic challenge in oncologic imaging (1) (2) (3) (4) (5) (6) (7) (8) . We sought to determine the outcomes of axillary lymphadenopathy after COVID-19 vaccination on breast imaging examinations.

In this IRB-approved HIPAA compliant retrospective study, we identified patients who received the COVID-19 vaccine and had breast imaging between 12/30/2020 and 4/12/2021 at 17 sites across one institution. Follow-up exams were recorded through 12/10/2021. Seven radiologists extracted clinicopathologic data and vaccine information from the medical records. The original radiology reports were used for imaging characteristics. Long-axis lymph node measurements were recorded. Statistics were calculated in Excel and Mann-Whitney U tests in SPSS software (SPSS, Chicago, Ill).

Of the 1217 patients that received the COVID-19 vaccination and had breast imaging, 537 (44%) had lymphadenopathy identified on at least one imaging exam. 823 patients (68%) presented for screening (Table E1) (Table E1 ).

Patients demonstrated lymphadenopathy as early as one day following the first dose and as late as 71 days following the second dose. The timing was different between the groups with and without lymphadenopathy; lymphadenopathy was more likely to be seen within 14 days after vaccination and was rare after 50 days after the 2nd dose ( Figure 1A ).

Eight percent (43/537) of patients underwent a biopsy; 34 (79%) had benign results ( Figure 2) and 9 (21%) had malignant results (Table E2 ). Four patients were diagnosed with metastatic breast cancer ( Figure E1 ); all had suspicious concurrent mammographic findings in the ipsilateral breast. Four patients were diagnosed with lymphoma; three patients already had known diagnoses, and the fourth patient presented with bilateral lymphadenopathy ( Figure E2 ).

One patient with a known history of lung cancer was diagnosed with lung cancer metastatic to an axillary lymph node. 

This is the largest study to evaluate axillary lymphadenopathy, with long-term follow-up of six months following the COVID-19 vaccination. Adenopathy is a common side-effect identified within 44% of our patients, with persistent lymphadenopathy seen up to 43 weeks after vaccination. Our findings suggest that patients should not delay their screening mammogram because they were recently vaccinated. The Moderna vaccine was significantly more associated with lymphadenopathy compared to Pfizer, consistent with a recent study that evaluated axillary adenopathy on chest CT (7) . Prior to the COVID-19 vaccine era, axillary adenopathy in women with an otherwise normal mammogram was reported in 0.02-0.04% of screening mammograms (4). In our large cohort with extended follow-up, there were no new diagnoses of malignancy during the follow-up period. The time to resolution of reactive lymphadenopathy was variable, with persistent lymphadenopathy seen up to 43 weeks after vaccination. This is even longer than a case of persistent FDG-PET/CT uptake at 70 days after the second dose of COVID-19 vaccination (8) . Given the extended period of time to resolution, no short-term follow-up imaging should be recommended. This differs from current guidelines which recommends a short-term follow-up exam in 4-12 weeks following the second vaccine dose (4) .

Other studies with lower reported incidence of lymphadenopathy (3-16%) are based on selfreported symptoms or detection solely on mammography; in contrast, our study had an incidence of 44%. This difference reflects our practice pattern that includes axillary adenopathy seen on either mammography or breast ultrasound in both the screening and diagnostic setting. (2) . 

Lymphadenopathy in COVID-19 Vaccine Recipients: Diagnostic Dilemma in Oncologic Patients

Incidence of Axillary Adenopathy in Breast Imaging After COVID-19 Vaccination

Multidisciplinary Recommendations Regarding Post-Vaccine Adenopathy and Radiologic Imaging: Radiology Scientific Expert Panel

SBI Recommendations for the Management of Axillary Adenopathy in Patients with Recent COVID-19 Vaccination. Society of Breast Imaging website

Axillary lymphadenopathy at the time of COVID-19 vaccination: ten recommendations from the European Society of Breast Imaging (EUSOBI). Insights Imaging

Mitigating the Impact of Coronavirus Disease (COVID-19) Vaccinations on Patients Undergoing Breast Imaging Examinations: A Pragmatic Approach

Axillary Lymphadenopathy After Coronavirus Disease 2019 Vaccinations in Patients with Thoracic Malignancy: Incidence, Predisposing Factors, and Imaging Characteristics

Prevalence of Increased FDG PET/CT Axillary Lymph Node Uptake Beyond 6 Weeks after mRNA

Vaccination

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