Frontiers in Nuclear Medicine · Published 2026-07-28 · DOI 10.3389/fnume.2026.1832138
Joana do Mar Ferreira Machado, Robert Winzer, Rudi Apolle, Almuth Forberger, Kristof Zarschler, Torsten Knieß, Martin Kreller, Klaus Kopka, Oliver C. Kiß, Jan Dominik Kuhlmann, Pauline Wimberger, Matthias Miederer, Theresa Link
We report a case that combines several aspects of molecular diagnostics and clinical follow-up with innovative imaging of [89Zr]Zr-DFO-trastuzumab positron emission computed tomography (PET/CT) to depict human epidermal growth factor receptor 2 (HER2)-targeted tracer uptake in several metastatic sites in advanced platinum-resistant high-grade serous ovarian cancer (HGSOC). A 74-year-old woman underwent this procedure, and PET/CT images were interpreted alongside conventional biomarkers [CA125 and immunohistochemistry (IHC)] and contrast-enhanced computed tomography (CE-CT). PET imaging revealed intense tracer uptake in the primary ovarian tumour site (SUVratio 13.8), with corresponding HER2 + expression (3+) observed on the IHC of the primary tumour. Moreover, moderate uptake was observed in abdominal wall metastases (SUVratio 3.6) and near-background uptake in hepatic lesions (SUVratio 1.6), consistent with image-suggestive spatial heterogeneity in HER2-targeted tracer uptake. CA125 measurements corroborated early biochemical response, with values declining from 676 to 254 U/mL after six weeks of trastuzumab deruxtecan (T-DXd) treatment as third-line therapy. Follow-up CE-CT showed qualitative regression of [89Zr]Zr-DFO-trastuzumab-avid lesions, despite non-measurable disease by RECIST and a subsequent CE-CT imaging after 20 weeks demonstrated a mixed response pattern, without a clear relationship to pre-T-DXd [89Zr]Zr-DFO-trastuzumab uptake. This case study illustrates how integrating non-invasive [89Zr]Zr-DFO-trastuzumab PET molecular imaging with conventional radiology, IHC, and biochemical markers within the clinical pathway may support individualised therapeutic decision-making.
Abstract from DOAJ. Public domain (CC0 1.0).
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Machado, J., Winzer, R., Apolle, R., et al. (2026). Case Report: Non-invasive [89Zr]Zr-DFO-trastuzumab positron emission tomography in the multimodal characterisation of platinum-resistant high-grade serous ovarian cancer. Frontiers in Nuclear Medicine. https://doi.org/10.3389/fnume.2026.1832138