[18F] FDG PET/CT and Head and Neck MRI in the Diagnosis and Prognosis of Moroccan Patients With Nasopharyngeal Carcinoma

Abstract

Purpose: While nasopharyngeal carcinoma (NPC) management in Morocco is still based on conventional work-ups: a head and neck computed tomography (HN-CT), thoracic and abdominal CT and bone scan, the combination of HN magnetic resonance imaging (HN-MRI) and 2-Deoxy-2-[18F] fluoro-D-glucose positron emission tomography/computed tomography ([18F] FDG PET/CT) is now widely used in the diagnostic and follow-up of this malignancy.Methods: In this prospective study, [18F] FDG PET/CT and HN-MRI outcomes of 117 NPC patients diagnosed between January 2017 and December 2018 were investigated in order to assess their usefulness in routine management of Moroccan patients with NPC. The concordance between HN-MRI and [18F] FDG PET/CT in Tumor (T) and Nodal (N) classification was assessed and the association between [18F] FDG PET/CT metabolic parameters (Tumor- maximum standardized uptake value (T-SUV max), Nodal (N-SUV max), node-to-tumor SUV ratio (NTR) and distant metastasis (M-SUV max), TNM staging system, NPC stages and patient’s survival outcomes was evaluated. Results: Our results showed a moderate concordance between T-TEP and T-MRI categories with a Cohen kappa coefficient (k) at 0.45, and a mediocre concordance between N-TEP and N-MRI (k=0.3). Metabolic parameters of the [18F] FDG PET/CT were assessed; N-SUV max values were significantly higher in patients with advanced nodal involvement, with a mean of 7.4, 9.7 and 11.0 for patients with N1, N2 and N3 nodal categories, respectively (p<0.05). overall, N-SUV max, NTR were independent prognostic markers for overall survival and progression free survival in Moroccan NPC patients (p<0.05).Conclusion: Our findings provide additional evidence into the complementary roles of HN-MRI and [18F] FDG PET/CT in TNM and overall staging of NPC. To the best of our knowledge, this is the first Moroccan study to highlight N-SUV max and NTR derived from [18F] FDG-PET/CT as promising metabolic biomarkers for NPC prognosis.