Title:Challenging Axillary Lymph Nodes on PET/CT in Cancer Patients throughout
COVID-19 Vaccination Era
Volume: 30
Issue: 10
Author(s): Alessia Giordano, Rosj Gallicchio, Mariarita Milella, Rebecca Storto, Anna Nardelli, Teresa Pellegrino, Antonio Nappi, Michele Di Cosola and Giovanni Storto*
Affiliation:
- Department of Nuclear Medicine, IRCCS CROB Referral Cancer Center of Basilicata, Rionero in Vulture, Italy
Keywords:
Vaccine, COVID-19, PET/CT, cancer, lympho-adenopathy, lymph nodes.
Abstract:
Background: The unexpected detection of axillary lymphadenopathy (AxL) in cancer patients (pts)
represents a real concern during the COVID-19 vaccination era. Benign reactions may take place after vaccine
inoculation, which can mislead image interpretation in patients undergoing F-18-FDG, F-18-Choline, and
Ga-68-DOTATOC PET/CT. They may also mimic loco-regional metastases or disease. We assessed PET/CT
findings after COVID-19 first dose vaccination in cancer patients and the impact on their disease course management.
Methods: We evaluated 333 patients undergoing PET/CT (257 F-18-FDG, 54 F-18-Choline, and 23 Ga-68
DOTATOC) scans after the first vaccination with mRNA vaccine (Pfizer-BioNTech) (study group; SG). The
uptake index (SUVmax) of suspected AxL was defined as significant when the ratio was > 1.5 as compared to
the contralateral lymph nodes. Besides, co-registered CT (Co-CT) features of target lymph nodes were evaluated.
Nodes with aggregate imaging positivity were further investigated.
Results: Overall, the prevalence of apparently positive lymph nodes on PET scans was 17.1% during the vaccination
period. 107 pts of the same setting, who had undergone PET/CT before the COVID-19 pandemic,
represented the control group (CG). Only 3 patients of CG showed reactive lymph nodes with a prevalence of
2.8% (p < 0.001 as compared to the vaccination period). 84.2% of SG patients exhibited benign characteristics
on co-CT images and only 9 pts needed thorough appraisal.
Conclusion: The correct interpretation of images is crucial to avoid unnecessary treatments and invasive
procedures in vaccinated cancer pts. A detailed anamnestic interview and the analysis of lymph nodes’ CT
characteristics, after performing PET/CT, may help to clear any misleading diagnosis.
