Nuklearmedizin 2021; 60(02): 132
DOI: 10.1055/s-0041-1726702
Leuchtturm
Bildgebung und Therapie

A new horizon for breast cancer staging: first evidence from simultaneous PET-MRI targeting the fibroblast activating protein (FAP)

P Backhaus
1   University Hospital Münster, Department of Nuclear Medicine, Münster
,
MC Burg
2   University Hospital Münster, Department of Radiology, Münster
,
W Roll
1   University Hospital Münster, Department of Nuclear Medicine, Münster
,
F Büther
1   University Hospital Münster, Department of Nuclear Medicine, Münster
,
HJ Breyholz
1   University Hospital Münster, Department of Nuclear Medicine, Münster
,
SB Weigel
2   University Hospital Münster, Department of Radiology, Münster
,
W Heindel
2   University Hospital Münster, Department of Radiology, Münster
,
M Pixberg
1   University Hospital Münster, Department of Nuclear Medicine, Münster
,
P Barth
3   University Hospital Münster, Gerhard-Domagk Institute for Pathology, Münster
,
J Tio
4   University Hospital Münster, Department of Gynecology & Obstetrics, Münster
,
M Schäfers
1   University Hospital Münster, Department of Nuclear Medicine, Münster
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Ziel/Aim In the management of breast cancer novel imaging strategies are warranted to further improve the staging in individual patients. The fibroblast activating protein (FAP) is abundantly expressed in breast cancer stroma. The aim of this study was to evaluate the potential of FAP-directed breast PET-MRI and whole-body PET using the FAP ligand 68Ga-FAPi-46 (FAPi) for staging of local disease progression and metastases.

Methodik/Methods In 14 female patients with breast cancer, we retrospectively analyzed a total of 16 68Ga-FAPi-PET scans performed on clinical grounds (13 PET scans to complement staging at primary diagnosis, 2 for re-staging after neoadjuvant chemotherapy and 1 for suspected relapse). 30 min after injection of an average dose of 155 MBq 68Ga-FAPi patients underwent a 25-min breast PET-MRI including diagnostic breast MRI. 1 h p.i. patients either received whole-body PET-MRI or PET-CT.

Ergebnisse/Results Strong tracer accumulation was observed in every primary untreated breast cancer (mean of the patient’s maximal Standardized Uptake Values, SUVmax: 15.1, range: 8.7 – 29.9) leading to upstaging of the T-stage in one patient and to a change in surgical breast management in another patient. Reliable uptake was observed in axillary lymph node metastases (mean SUVmax at affected surgical level 1 lymph nodes: 12.0, range: 3.3-22.4). 68Ga-FAPi-46-PET indicated a spread to otherwise unaffected levels in 5 patients resulting in upstaging of the N-stage in 3/14 patients and a change of surgical management in one. In the two patients with distant metastases 68Ga-FAPi-46-PET revealed novel metastases in respect to 18F-FDG-PET and morphological imaging. PET-MRI re-staging after neoadjuvant chemotherapy predicted classification of pathological remission in both cases.

Schlussfolgerungen/Conclusions Combining 68Ga-FAPi-46 targeting the fibroblast activating protein with simultaneous breast PET-MRI and whole-body PET adds significant and incremental diagnostic information to the local and whole-body staging of breast cancer patients.



Publication History

Article published online:
08 April 2021

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