Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
INTRO: [18F]- FDG PET is a commonly used, highly sensitive imaging strategy that detects cancer cell metabolism, but is known for its lack of specificity. In head and neck cancer patients, nonspecific uptake in reactive lymph nodes and post-treatment inflammation is often read as positive. To overcome these limitations, we use [89Zr]-panitumumab, a radiolabeled antibody that targets EGFR, as an additional scan to further assess indeterminate lesions in head and neck cancer.
METHOD: Patients with one or more lesions with increased standard uptake value (SUV) that were considered “indeterminate” by formal nuclear medicine read on conventional (FDG PET/CT) imaging were eligible for inclusion. The patients were enrolled on NCT# 05747625 and underwent a PET/CT scan using [89Zr] Panitumumab. The scans were analyzed by collecting the standardized uptake values (SUV) and the volumes of the regions of interest. The patients’ charts were monitored over time for definitive histologic diagnosis. If squamous cell carcinoma was confirmed, the lesion on the PET scan was deemed as positive.
RESULTS: A total of 15 patients have been enrolled with a total of 50 lesions identified as indeterminate on FDG-PET, 4 of which are excluded from this analysis due to being diagnosed as small cell lung cancer on pathology[ER1] . On the 89Zr-panitumumab scan, the SUVmax of positive lesions (3.20 ± 1.63) was significantly higher and almost double that of negative lesions (1.85 ± 0.76; p = 0.009). Receiver operating curves (ROC) were calculated for each type of scan. As previously shown, the 18F-FDG scan has better sensitivity than the 89Zr-panitumumab scan (72% vs 55%), but the specificity of the 89Zr-panitumumab scan was far superior to 18F-FDG (91% vs 40%).
CONCLUSION: When paired with [18F] FDG PET/CT , [89Zr] Panitumumab PET/CT is a useful, safe, and highly specific imaging tool to assess indeterminate lesions.