Novel⁶⁸Ga-FAPI PET/CT Offers Oncologic Staging Without COVID-19 Vaccine–Related Pitfalls

Abstract

In the setting of ongoing COVID-19 vaccination, vaccine-related tracer uptake in locoregional lymph nodes has become a well-known issue in tumor staging by 18 F-FDG PET/CT. 68 Ga-FAPI PET/CT is a new oncologic imaging tool that may overcome this limitation.Methods: We assessed post-vaccine, head-to-head and same-day 18 F-FDG and 68 Ga-FAPI-46 PET/CT findings in a series of 11 patients from a large prospective imaging registry. All patients with documented tracer uptake in locoregional lymph nodes on PET/CT or PET/MRI, following vaccination within 6 weeks, were eligible for investigation.Result: Significant visual lymph node uptake adjacent to the injection site was noted in 11/11 (100%) patients with 18 F-FDG PET/CT versus 0/11 (0%) with 68 Ga-FAPI PET/CT. 18 F-FDG detected 73% and 68 Ga-FAPI PET/CT 94% of all tumor lesions. Conclusion:In this case-series study, 68 Ga-FAPI showed its potential to avoid 18 F-FDG-PET/CT post-vaccination pitfalls and presented superior tumor localization.Squibb, Celgene, Eisbach Bio, Roche/Genentech; he holds ownership and serves on the Board of Directors of Pharma15, all outside the submitted work.Benedikt M. Schaarschmidt received a research grant from PharmaCept for an undergoing investigator-initiated study not related to this paper.

[18F]FES PET Resolves the Diagnostic Dilemma of COVID-19-Vaccine-Associated Hypermetabolic Lymphadenopathy in ER-Positive Breast Cancer

“…Vaccine-induced accumulation in the ipsilateral axillary lymph nodes is known to be observed not only with FDG but also with [ 11 C] Choline [19], [ 18 F]Choline [20], [ 18 F] prostate-specific membrane antigen (PSMA) [20], [ 68 Ga]DOTA-peptide (DOTATATE) [21], and [ 177 Lu] Lu-DOTATATE PRRT post-therapy planar scintigraphy, as well as single-photon emission computed tomography with computed tomography (SPECT/CT) [22]. On the other hand, [ 68 Ga] fibroblast-activation protein inhibitor (FAPI) was reported to show no accumulation in the enlarged axillary lymph nodes after vaccine administration, similar to our report on [ 18 F]FES, which may be useful in distinguishing lymph node metastasis [23].…”

Case report: diagnosis and treatment of advanced high-grade serous ovarian carcinoma aided by 68Ga-FAPI PET/MR scan

“…In some cases, 68 Ga-FAPI provided clearer imaging and better differentiation between tumors and surrounding tissues, particularly in cancers where 18 F-FDG might not perform as well due to factors like inflammation or overlap in uptake by normal tissues. 68 Ga-FAPI has shown promise in detecting distant metastases, especially in tumors that don't typically accumulate 18 F-FDG well or in cases where 18 F-FDG PET/CT might not provide sufficient information [10,15,16]. However, the advantages of 68 Ga-FAPI may vary depending on the type and stage of cancer, and it may not necessarily replace 18 F-FDG entirely, as both tracers have their specific clinical applications.…”

COVID-19 Vaccines: A Radiological Review of the Good, the Bad, and the Ugly

“…Increased FDG uptake has also been observed in the spleen after COVID-19 vaccination. 92 Inflammatory changes have been seen in the ipsilateral breast of a 60-year-old woman 5 days after a booster dose of Pfizer-BioNTech vaccine on mammography seen as a new asymmetry in the upper breast that was categorized as probably a benign lesion (Breast Imaging Reporting and Data System [BI-RADS] category 3). The patient's follow-up mammography 2 months later showed resolution of the asymmetry.…”