Understanding COVID Vaccination and Its Implication in Cancer Patients’ Imaging of Lymph Nodes by PET-CT

Abstract

(1) Background: The appearance of enlarged lymph nodes on imaging adds another layer of complexity to the differential diagnosis of disease progression versus immune response to COVID-19 vaccines. Our aim was to find an optimal timing between the vaccination and the PET-CT scan. (2) Methods: 25 cancer patients with 18F-FDG PET-CT evaluations and a history of COVID-19 vaccination between September 2021 and December 2021 were retrospectively analyzed to characterize the lymph nodes related to the time interval from COVID vaccination. (3) Results: All patients presented one or more adenopathies localized in the ipsilateral axilla (96%), ipsilateral cervical area (20%), ipsilateral retropectoral (20%) and pulmonary hilum (8%). The median value of SUVmax was 3.5 ± 0.5. There was a significant indirect correlation between SUVmax and the time passed between the vaccination and the PET CT (Pearson Correlation r = −0.54, p = 0.005). There was no significant difference (p = 0.19) in the SUVmax value in patients receiving Moderna mRNA-1273 vaccine vs. BNT162b2 mRNA Pfizer vaccine. (4) Conclusions: Lymph node enlargement is commonly seen in patients post-vaccination for COVID-19 and must be differentiated from disease progression. The data from our study strongly suggests that the minimum interval of time between an mRNA vaccine and a PET-CT should be more than six weeks.

Prolonged generalized immune response on 18F-FDG PET/CT following COVID-19 vaccination

“…The antigens present in the vaccines interact with the host leading to increased immunological response, which leads to inflammatory reaction at the site of injection and surrounding lymphoid tissue. The inflammatory changes are due to release of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α), prostaglandins, and interleukins (IL-1 and 6), by immune cells such as macrophages, dendritic cells, and monocytes mimicking innate and adaptive immune response to a natural infection, resulting in lymphadenopathy with swollen and occasionally painful lymph nodes [18] , [19] , [20] , [21] .…”

Tolerated Re-Challenge of Immunotherapy in a Patient with ICI Associated Myocarditis: A Case Report and Literature Review

“…Nevertheless, myocarditis associated with DRESS is associated with a similarly high mortality rate, approximately 40% [72]. When comparing the rarity of Immune Checkpoint Inhibitor-Induced Myocarditis to COVID-19-associated myocarditis, this discrepancy may stem from challenges related to misclassification and the intricate diagnosis of cardiac events triggered by ICIs, or other rare and unexpected adverse events related to the COVID-19 vaccine, particularly amid the ongoing COVID-19 pandemic [73][74][75][76][77][78]. A systematic review encompassing 43 articles, ultimately identified 51 patients with COVID-19-associated myocarditis based on clinical diagnosis.…”