COVID-19 Vaccination and Imaging Misinterpretation: An Interview With Lacey McIntosh, DO, MPH

According to a recent statement by President Joe Biden, the United States plans to offer vaccination against SARS-CoV-2, the virus that causes COVID-19, to all adults in the United States by May 2021, 100 across the country have at least 1 dose of one currently approved vaccine. 2

The vaccination program should improve overall survival in the population of cancer patients, as this group is at high risk of COVID-19-related mortality. However, the clinical considerations related to vaccination in this population are not yet clear, and some research suggests that oncologists and patients be aware of the possible manifestations of vaccination when imaging and the possible consequences for the assessment of the disease, monitoring treatment and be aware of treatment should make decisions.

A recent article published in the American Journal of Roentgenology suggests that vaccination can lead to enlargement of the axillary, supraclavicular, and / or cervical lymph nodes on the side of the injection. According to the authors, such an enlargement can in some cases lead to confusing results and / or even to a misinterpretation of positron emission tomography / computed tomography (PET / CT) of fluorodeoxyglucose (FDG).

While lymphadenopathy has been reported with other vaccines, particularly against seasonal influenza and human papillomavirus, the widespread use of SARS-CoV-2 vaccination in the clinical community requires an awareness of the potential for imaging outcomes, particularly with FDG -PET / CT. The clinician's awareness of the vaccination site and timing can help coordinate the imaging to avoid these manifestations, which in some cases can affect the accuracy of the exams. Given the number of cancer patients who have received or are likely to receive vaccinations, some scans may not be interpretable, leading to treatment indecision in the face of potentially aggressive diseases.

To that end, Lacey McIntosh, DO, MPH, assistant professor at the University of Massachusetts Medical School at Worcester, and the study's first author discussed the implications of this research.

What is the dilemma in performing PET / CT on patients recently vaccinated against COVID-19?

Dr. McIntosh: The diagnostic dilemma we are facing is that the imaging manifestations of a recent COVID-19 vaccine can mimic cancer, especially on PET / CT. The vaccine causes tracer uptake and sometimes enlargement of the lymph nodes of the armpit, supraclavicular region, and neck on the side of the administration.

PET / CT is used for a variety of indications in oncology, including lesion characterization, disease staging, monitoring of response to treatment, and monitoring for recurrence. Treatment decisions and disease status often depend heavily on the results of this imaging. These studies can be difficult for doctors to obtain for their patients. So we want to make sure that when they are done they are done well and give us the best chance of getting the information we need with clear results.

In some cases, a recent pre-imaging vaccine can potentially produce confusing results that render the study ineffective and even lead to misinterpretation if information about the vaccination is not available to the reading radiologist.

This article originally appeared on Cancer Therapy Advisor