[¹⁸F]F FDG PET/CT and [⁶⁸Ga]Ga-FAPI-4 PET/CT Imaging Following EGFR Targeted Erlotinib Treatment Toward Accurate Disease Status Evaluation in Metastatic or Advanced Head and Neck squamous Cell Carcinoma (HNSCC): A Complementary Role?

Abstract

Head and neck squamous cell carcinoma (HNSCC) comprises a heterogeneous group of malignancies affecting the oral cavity, pharynx, and larynx, representing the seventh most common malignancy worldwide. Management of HNSCC with standard treatments remains inadequate in a substantial fraction of patients. Epidermal growth factor receptor (EGFR) is a novel treatment target, which is overexpressed in approximately 90% of HNSCC, making EGFR inhibitors such as erlotinib a promising therapeutic agent. [¹⁸F]F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) serves as the standard imaging modality for HNSCC management, while [⁶⁸Ga]Ga-fibroblast activation protein inhibitor-04 (FAPI-04) represents an emerging radiotracer showing superior performance in specific clinical scenarios. We herein present two HNSCC patients who underwent two imaging modalities ([¹⁸F]F-FDG PET/CT and [⁶⁸Ga]Ga-FAPI-04 PET/CT) following erlotinib treatment. In the first patient, [¹⁸F]F-FDG-PET/CT failed to identify metastatic cervical and mediastinal lymph nodes and skeletal lesions that were clearly visualized on [⁶⁸Ga]Ga-FAPI-04 PET/CT. In patient 2, post-erlotinib, [⁶⁸Ga]Ga-FAPI-04 PET/CT demonstrated reduced uptake in primary and lymph nodal lesions compared to [¹⁸F]F-FDG PET/CT. These findings suggest that both molecular imaging agents provide complementary information for accurate disease status evaluation and treatment response assessment in advanced HNSCC patients receiving erlotinib therapy.

Keywords

head and neck squamous cell carcinoma (HNSCC) - epidermal growth factor receptor (EGFR) - erlotinib - [¹⁸F] F FDG PET/CT - [⁶⁸Ga]Ga FAPI-04 PET/CT - treatment response - complementary imaging

Publikationsverlauf

Artikel online veröffentlicht:
05. Januar 2026

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