Value of positron emission tomography with 18-fluorodeoxyglucose (FDG-PET) in early detection of residual tumor in oro-pharyngeal-laryngeal carcinoma]

To evaluate and compare the performances of FDG-PET imaging, MRI and clinical examination in the detection of residual tumour 3 months after treatment of patients with head and neck squamous cell carcinoma.A consecutive sample of 50 patients with squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx or larynx, or a cervical lymph node metastasis from an unknown primary site excluding T1 lip and T1 vocal cord tumours.Treatment outcome was assessed after 3 months by clinical examination, MRI, and FDG-PET scan. Sensitivity, specificity and accuracy were calculated relative to proven biopsy of residual tumour or a clinical follow-up of 4 months.Residual cancer was confirmed in 8 patients (16%), while the clinical follow-up was unsuspicious in the remaining 42 patients. PET-FDG had a sensitivity of 100% as compared to MRI (88%) and clinical examination (63%). Specificity was higher for clinical examination (90%), intermediate for MRI (83%) and lowest for PET-FDG (74%).This study finds very high sensitivity for PET-FDG in the detection of residual tumour. However, its lower specificity, lack of anatomical resolution, and high cost, require further studies to determine its role in routine screening.