Alina Toni Küper, Ieva Ciuciulkaite, Anja Welt, Sofia Carrilho Vaz, Ilektra Antonia Mavroeidi, Rainer Hamacher, Tristan Demmert, Kim Magaly Pabst, Alexandros Moraitis, Loic Djaileb, Robert Seifert, Lale Umutlu, Martin Schuler, Ken Herrmann, Wolfgang Peter Fendler, Sherko Kümmel, David Kersting
This single-center subgroup analysis of a prospective trial (NCT04571086) at University Hospital Essen investigated tumor uptake and detection rates of [68Ga]Ga-FAPI-46- versus [18F]FDG PET in triple-negative breast cancer (TNBC) patients undergoing initial or follow-up staging. Lesions were recorded across anatomical regions, with detection efficacy, uptake values, tumor-to-liver ratios, and tumor volumes assessed. 22 patients were included (initial- n = 10, follow-up staging n = 12). No significant difference in region-based detection rates was observed between [18F]FDG- (93%, 53/57 regions) and [68Ga]Ga-FAPI-46 PET (93%, 53/57 regions) (McNemar p = 1.0). Three patients (25%) at follow-up staging showed an average tumor SUVmean ≥5 on [68Ga]Ga-FAPI-46 PET; 2/3 showed SUVmax >10 in most lesions. Mean tumor volume was higher for [68Ga]Ga-FAPI-46, though not statistically significant at initial- (50.1 ± 120.8 mL vs. 11.9 ± 18.5 mL) and follow-up staging (102.2 ± 122.3 mL vs. 79.0 ± 90.4 mL). [⁶⁸Ga]Ga-FAPI-46 PET demonstrated comparable detection in TNBC; high tumor uptake in a subset, supporting its theranostic potential.