key: cord-0714218-dehxbg5p
authors: Brown, Adam Harry; Shah, Sweni; Groves, Ashley M.; Wan, Simon; Malhotra, Anmol
title: The Challenge of Staging Breast Cancer With PET/CT in the Era of COVID Vaccination
date: 2021-04-02
journal: Clin Nucl Med
DOI: 10.1097/rlu.0000000000003683
sha: 9adc8680e2acad3816303b37b6bada736fb9a9c7
doc_id: 714218
cord_uid: dehxbg5p

We report a case series of biopsy-proven reactive axillary lymph nodes, which were avid on FDG PET/CT in breast cancer patients post COVID-19 vaccination. With 4 cases presenting in a consecutive 10-day period, it became apparent that metabolically active axillary lymphadenopathy is an adverse effect of COVID-19 vaccines, currently being deployed worldwide. This may lead to patients undergoing unnecessary biopsy. We have started taking a COVID-19 vaccine status history before PET/CT. If enlarged/metabolically active axillary nodes are identified in the ipsilateral vaccinated arm, then axillary ultrasound at 4 weeks is suggested.

There is a small focus of FDG avidity in the deltoid muscle in the right upper arm at the known injection site (blue arrow). This patient also underwent ultrasound-guided biopsy of the lymph node, which was shown to be reactive with no evidence of malignancy. At this time, the UK vaccination program was ahead of most other countries in the world, having offered the first dose of the vaccine to all over 70s by mid-February 2021. Being largely similar in age demographic, it became apparent that we would be seeing an increasing number of recently vaccinated patients presenting for surveillance cancer imaging. A new approach was needed to prevent unnecessary interventions, and our institution began to collect information about vaccination such as date, type, first/second dose, and arm vaccinated before PET/CT studies to avoid this pitfall in future patients. This was yet another case of axillary lymph node avidity contralateral to the known breast cancer but ipsilateral to the recently vaccinated arm. On this occasion, however, a conservative approach was taken, and as the lymph nodes were of normal size on CT, the patient was scheduled for a follow-up ultrasound 4 weeks later. It is important to stress that if the avid lymph nodes are ipsilateral to the breast cancer, or enlarged on CT, emergent further workup with ultrasound ± biopsy is warranted. There was also intense uptake in a nonenlarged left subpectoral lymph node (C, arrow). Further questioning revealed the patient had received the COVID-19 vaccine in the left arm less than 3 weeks earlier. Further research on clarifying the expected time course of axillary lymph node FDG avidity and associated SUV values on PET/CT is needed, especially as new COVID-19 vaccinations to target emerging variants may be introduced in the future. This will also ensure these patients are appropriately managed going forward.

Defining the role of PET-CT in staging early breast cancer

Breast cancer imaging with PET based radiopharmaceuticals other than 18 F-FDG

Spectrum of the breast lesions with increased 18