ABSTRACT
RATIONALE AND OBJECTIVES: Reported incidence of vaccine-induced adenopathy varies widely, with higher estimates in early reports and small series. Objective was to evaluate a large sample of vaccinated patients undergoing screening mammography, to determine callback rates associated with vaccine-induced adenopathy and their outcomes. MATERIALS AND METHODS: Single-institution retrospective review of patients who received at least 1 dose of a COVID-19 vaccine prior to presentation for screening mammography from January 15 through May 31, 2021. Patient-related vaccination information (dose, brand, arm, date) was obtained by mammography technologists and available for interpreting radiologists. Patients recalled for axillary adenopathy were included; other causes for recall were excluded. Follow-up imaging and outcomes were tracked. Wilcoxon rank-sum test, Fisher exact test, multivariable logistic regression modeling, and receiver operating characteristic curve analyses were utilized. All tests were two-sided; p < 0.05 considered statistically significant. RESULTS: Total of 2304 vaccinated patients underwent screening mammography; 24 (1.0%) recalled for ipsilateral adenopathy. There was no significant difference in presence of adenopathy associated with patient age, dose, or brand of vaccine. Presence of adenopathy significantly decreased as days from vaccination increased (p < 0.001). Receiver operating characteristic curve suggested 28.5 days as the best cutoff point to distinguish presence or absence of adenopathy on mammogram. Of 24 callbacks, 13 (54.2%) had benign results, 2 (8.3%) are still undergoing surveillance, and 9 (37.5%) are overdue for subsequent follow-ups. No cases resulted in biopsy or malignancy. CONCLUSION: Low recall rates related to vaccine-induced adenopathy are achievable and can limit unnecessary workups, improve access, and promote flexible timing of vaccinations and screening exams.