@article {El-Sayede633, author = {Mohamed S El-Sayed and Godfrey N Wechie and Chen Sheng Low and Oludolapo Adesanya and Nikhil Rao and Vincent J Leung}, title = {The incidence and duration of COVID-19 vaccine-related reactive lymphadenopathy on 18F-FDG PET-CT}, volume = {21}, number = {6}, pages = {e633--e638}, year = {2021}, doi = {10.7861/clinmed.2021-0420}, publisher = {Royal College of Physicians}, abstract = {Objectives Reactive axillary lymph nodes (ALN) may occur post-COVID-19 vaccination. This may be confused with malignant nodal metastases on oncological imaging. We aimed to determine the reactive ALN incidence and duration on 18F-fluorodeoxyglucose positron emission tomography {\textendash} computed tomography (18F-FDG PET-CT), and its relationship with gender, age and vaccine type.Methods A retrospective study was performed. Two-hundred and four eligible patients had 18F-FDG PET-CT between 01 January 2021 and 31 March 2021, post-vaccination with Pfizer-BioNTech or Oxford-AstraZeneca vaccine. Image analysis was performed on dedicated workstations. SPSS was used for statistical analysis.Results Thirty-six per cent of patients had reactive ALN until 10 weeks post-vaccination; reducing in frequency and intensity with time. Women were more likely to have reactive ALN compared with men. The frequency and intensity were higher in patients aged \<65 years compared with those aged >=65 years. However, no difference was found between both vaccine types in our study cohort.Conclusions Physicians{\textquoteright} awareness of COVID-19 vaccine-related reactive ALN on 18F-FDG PET-CT is important to avoid inappropriate upstaging of cancers.}, issn = {1470-2118}, URL = {https://www.rcpjournals.org/content/21/6/e633}, eprint = {https://www.rcpjournals.org/content/21/6/e633.full.pdf}, journal = {Clinical Medicine} }