Intra-image referencing for simplified assessment of HER2-expression in breast cancer metastases using the Affibody molecule ABY-025 with PET and SPECT.
Eur J Nucl Med Mol Imaging
; 44(8): 1337-1346, 2017 Aug.
Article
en En
| MEDLINE
| ID: mdl-28261749
ABSTRACT
PURPOSE:
In phase I/II-studies radiolabelled ABY-025 Affibody molecules identified human epidermal growth factor receptor 2 (HER2) expression in breast cancer metastases using PET and SPECT imaging. Here, we wanted to investigate the utility of a simple intra-image normalization using tumour-to-reference tissue-ratio (T/R) as a HER2 status discrimination strategy to overcome potential issues related to cross-calibration of scanning devices.METHODS:
Twenty-three women with pre-diagnosed HER2-positive/negative metastasized breast cancer were scanned with [111In]-ABY-025 SPECT/CT (n = 7) or [68Ga]-ABY-025 PET/CT (n = 16). Uptake was measured in all metastases and in normal spleen, lung, liver, muscle, and blood pool. Normal tissue uptake variation and T/R-ratios were established for various time points and for two different doses of injected peptide from a total of 94 whole-body image acquisitions. Immunohistochemistry (IHC) was used to verify HER2 expression in 28 biopsied metastases. T/R-ratios were compared to IHC findings to establish the best reference tissue for each modality and each imaging time-point. The impact of shed HER2 in serum was investigated.RESULTS:
Spleen was the best reference tissue across modalities, followed by blood pool and lung. Spleen-T/R was highly correlated to PET SUV in metastases after 2 h (r = 0.96, P < 0.001) and reached an accuracy of 100% for discriminating IHC HER2-positive and negative metastases at 4 h (PET) and 24 h (SPECT) after injection. In a single case, shed HER2 resulted in intense tracer retention in blood. In the remaining patients shed HER2 was elevated, but without significant impact on ABY-025 biodistribution.CONCLUSION:
T/R-ratios using spleen as reference tissue accurately quantify HER2 expression with radiolabelled ABY-025 imaging in breast cancer metastases with SPECT and PET. Tracer binding to shed HER2 in serum might affect quantification in the extreme case.Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Fragmentos de Péptidos
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Proteína Estafilocócica A
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Neoplasias de la Mama
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Regulación Neoplásica de la Expresión Génica
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Tomografía Computarizada de Emisión de Fotón Único
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Receptor ErbB-2
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Tomografía Computarizada por Tomografía de Emisión de Positrones
Tipo de estudio:
Prognostic_studies
Límite:
Adult
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Aged
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Humans
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Middle aged
Idioma:
En
Revista:
Eur J Nucl Med Mol Imaging
Asunto de la revista:
MEDICINA NUCLEAR
Año:
2017
Tipo del documento:
Article
País de afiliación:
Suecia