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

Purpose/Objective(s) 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). Materials/Methods 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. Results 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). Conclusion 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. Author Disclosure:J. Driessen: None. M. Philippens: None. J. Huijbregts: None. F. Pameijer: None. L. Janssen: None. W. Grolman: None. C. Terhaard: None. Copyright © 2016 Published by Elsevier Inc.