TY  - JOUR
A1  - Weich, Alexander
A1  - Werner, Rudolf A.
A1  - Buck, Andreas K.
A1  - Hartrampf, Philipp E.
A1  - Serfling, Sebastian E.
A1  - Scheurlen, Michael
A1  - Wester, Hans-Jürgen
A1  - Meining, Alexander
A1  - Kircher, Stefan
A1  - Higuchi, Takahiro
A1  - Pomper, Martin G.
A1  - Rowe, Steven P.
A1  - Lapa, Constantin
A1  - Kircher, Malte
T1  - CXCR4-Directed PET/CT in Patients with Newly Diagnosed Neuroendocrine Carcinomas
JF  - Diagnostics
N2  - We aimed to elucidate the diagnostic potential of the C-X-C motif chemokine receptor 4 (CXCR4)-directed positron emission tomography (PET) tracer \(^{68}\)Ga-Pentixafor in patients with poorly differentiated neuroendocrine carcinomas (NEC), relative to the established reference standard \(^{18}\)F-FDG PET/computed tomography (CT). In our database, we retrospectively identified 11 treatment-naïve patients with histologically proven NEC, who underwent \(^{18}\)F-FDG and CXCR4-directed PET/CT for staging and therapy planning. The images were analyzed on a per-patient and per-lesion basis and compared to immunohistochemical staining (IHC) of CXCR4 from PET-guided biopsies. \(^{68}\)Ga-Pentixafor visualized tumor lesions in 10/11 subjects, while \(^{18}\)F-FDG revealed sites of disease in all 11 patients. Although weak to moderate CXCR4 expression could be corroborated by IHC in 10/11 cases, \(^{18}\)F-FDG PET/CT detected significantly more tumor lesions (102 vs. 42; total lesions, n = 107; p < 0.001). Semi-quantitative analysis revealed markedly higher 18F-FDG uptake as compared to \(^{68}\)Ga-Pentixafor (maximum and mean standardized uptake values (SUV) and tumor-to-background ratios (TBR) of cancerous lesions, SUVmax: 12.8 ± 9.8 vs. 5.2 ± 3.7; SUVmean: 7.4 ± 5.4 vs. 3.1 ± 3.2, p < 0.001; and, TBR 7.2 ± 7.9 vs. 3.4 ± 3.0, p < 0.001). Non-invasive imaging of CXCR4 expression in NEC is inferior to the reference standard \(^{18}\)F-FDG PET/CT.
KW  - CXCR4
KW  - NET
KW  - NEC
KW  - <sup>68</sup>Ga-Pentixafor
KW  - <sup>18</sup>F-FDG
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-234231
SN  - 2075-4418
VL  - 11
IS  - 4
ER  - 
TY  - JOUR
A1  - Serfling, Sebastian E.
A1  - Lapa, Constantin
A1  - Dreher, Niklas
A1  - Hartrampf, Philipp E.
A1  - Rowe, Steven P.
A1  - Higuchi, Takahiro
A1  - Schirbel, Andreas
A1  - Weich, Alexander
A1  - Hahner, Stefanie
A1  - Fassnacht, Martin
A1  - Buck, Andreas K.
A1  - Werner, Rudolf A.
T1  - Impact of tumor burden on normal organ distribution in patients imaged with CXCR4-targeted [\(^{68}\)Ga]Ga-PentixaFor PET/CT
JF  - Molecular Imaging and Biology
N2  - Background
CXCR4-directed positron emission tomography/computed tomography (PET/CT) has been used as a diagnostic tool in patients with solid tumors. We aimed to determine a potential correlation between tumor burden and radiotracer accumulation in normal organs.

Methods
Ninety patients with histologically proven solid cancers underwent CXCR4-targeted [\(^{68}\)Ga]Ga-PentixaFor PET/CT. Volumes of interest (VOIs) were placed in normal organs (heart, liver, spleen, bone marrow, and kidneys) and tumor lesions. Mean standardized uptake values (SUV\(_{mean}\)) for normal organs were determined. For CXCR4-positive tumor burden, maximum SUV (SUV\(_{max}\)), tumor volume (TV), and fractional tumor activity (FTA, defined as SUV\(_{mean}\) x TV), were calculated. We used a Spearman's rank correlation coefficient (ρ) to derive correlative indices between normal organ uptake and tumor burden.

Results
Median SUV\(_{mean}\) in unaffected organs was 5.2 for the spleen (range, 2.44 – 10.55), 3.27 for the kidneys (range, 1.52 – 17.4), followed by bone marrow (1.76, range, 0.84 – 3.98), heart (1.66, range, 0.88 – 2.89), and liver (1.28, range, 0.73 – 2.45). No significant correlation between SUV\(_{max}\) in tumor lesions (ρ ≤ 0.189, P ≥ 0.07), TV (ρ ≥ -0.204, P ≥ 0.06) or FTA (ρ ≥ -0.142, P ≥ 0.18) with the investigated organs was found.

Conclusions
In patients with solid tumors imaged with [\(^{68}\)Ga]Ga-PentixaFor PET/CT, no relevant tumor sink effect was noted. This observation may be of relevance for therapies with radioactive and non-radioactive CXCR4-directed drugs, as with increasing tumor burden, the dose to normal organs may remain unchanged.
KW  - CXCR4
KW  - C-X-C motif chemokine receptor 4
KW  - PET
KW  - [68Ga]PentixaFor
KW  - [177Lu]/[90Y]PentixaTher
KW  - theranostics
KW  - endoradiotherapy
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324622
VL  - 24
IS  - 4
ER  -