Prospective Comparative Study of Diffusion-Weighted MRI Versus FDG Positron Emission Tomography/Computed Tomography for the Detection of Recurrent Head and Neck Squamous Cell Carcinomas After (Chemo)Radiation Therapy

Abstract

This prospective study aimed to compare the diagnostic accuracy of diffusion weighted MRI (DW-MRI) to FDG PET-CT in the detection of local recurrent head and neck squamous cell carcinomas after (chemo)radiation ((C)RT). The institutional ethical committee approved this study and all patients signed written informed consent. Seventy-five patients clinically suspected of local recurrence after (C)RT for laryngeal, hypopharyngeal or oropharyngeal cancer underwent a DW-MRI and an FDG PET-CT. Qualitative assessment of DW-MRI and FDG PET-CT was performed independently by a blinded experienced radiologist and a nuclear medicine physician respectively. Reference standard was the absence of biopsy proven local recurrence within 6 months following imaging. Seventy patients were suitable for analysis. Fifty percent (35/70) had local recurrence. Seventy-three percent (51/70) of the FDG PET-CTs were positive compared to 46% (32/70) of the DW-MRI. FDG PET-CT had an area under the curve 0.71 compared to 0.73 for MR-DWI (P = 0.85). The sensitivity of FDG PET-CT was 97% compared to 69% for DW-MRI (P = <0.01). The specificity of FDG PET-CT was 77% compared to 46% for DW-MRI (P = <0.01). DW-MRI showed similar diagnostic accuracy, superior specificity but inferior sensitivity compared to FDG PET-CT. False negative results will cause delay in the detection of a recurrence and this will potentially influence the chance of successful salvage surgery. Therefore, based on these results, we consider FDG PET-CT to be superior to MR-DWI for the detection of early recurrent oropharyngeal, hypopharyngeal or laryngeal cancer after (chemo)radiation.