Application of 18F-FDG PET/MRI for Initial Staging in Locally Advanced Nasopharyngeal Carcinoma

• Background:

Nasopharyngeal carcinoma (NPC) is prevalent in Southeast Asia and North Africa, with 5% of newly diagnosed cases showing distant metastases. For N2-3 stage patients with high Epstein-Barr virus (EBV) DNA levels, the metastasis rate can reach 27.5%. Accurate detection at diagnosis is crucial for staging and treatment planning. While the National Comprehensive Cancer Network (NCCN) recommends fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for staging locally advanced NPC, traditional methods like chest CT or ultrasound may yield false negatives. PET/MRI offers improved accuracy and reduced false positives but is limited by high costs and low accessibility. This study examines the cost-effectiveness and clinical value of PET/MRI in NPC staging.

• Material and methods:

This study is a single-center prospective observational study. It will recruit patients aged 18 years or older with pathologically confirmed nasopharyngeal carcinoma (NPC) who have not received any NPC-related treatment and agree to participate. All participants will undergo PET/CT and PET/MRI to compare their diagnostic performance in detecting distant metastases, including sensitivity, specificity, and staging accuracy. The study will also evaluate the time efficiency and cost-effectiveness of PET/MRI to explore its clinical value and limitations.

• Expecting Results:

This study aims to demonstrate that PET/MRI has superior diagnostic accuracy over PET/CT in staging locally advanced nasopharyngeal carcinoma, especially in detecting distant metastases. Despite higher costs, PET/MRI's accuracy may streamline diagnosis, reduce unnecessary tests, and support precise treatment strategies, improving patient outcomes and quality of life. The results will provide evidence for its clinical use and guide future diagnostic improvements.

Inclusion criteria

• Pathologically diagnosed with nasopharyngeal carcinoma (NPC) through endoscopic biopsy at the hospital's otolaryngology department.
• Clinically staged as cT3-4/N2-N3.
• Age: 18 years and older.
• Participants must voluntarily sign an informed consent form, acknowledging understanding of the study objectives and potential risks.

Exclusion criteria

• Patients with poorly controlled diabetes. -Patients with a history of head and neck malignancies or a history of non- head and neck cancers with no evidence of disease for at least 3 years.
• Patients with clinical staging of cT1-2N0-1.
• Patients with factors that may affect PET/MRI image quality, such as implanted metal devices or MRI contraindications, or those with a history of contrast agent allergies.