The detection of local recurrent head and neck cancer with fluroine-18 fluorodeoxyglucose dual-head positron emission tomography

Primary tumors of the larynx and hypopharynx are preferably treated with hi gh-dose radiation therapy. In these patients, it may be difficult to distin guish recurrent disease from post-treatment reactions. The aim of the prese nt study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in the detection of local relapses of laryng eal or hypopharyngeal carcinoma after radiotherapy using a. dual-head PET c amera. Forty-eight patients (43 male, 5 female; mean age +/-SD, 61+/-9.5 ye ars) with suspected recurrent laryngeal or hypopharyngeal cancer were prosp ectively studied, The mean interval between initial treatment and suspicion of recurrent disease was 14.6 months (range: 3-100 months). FDG dual-head PET was followed by endoscopy with or without biopsy under general anaesthe sia within a period of 2 months in all patients, The mean period of follow- up after FDG dual-head PET was 13.7 months. In 19 out of 31 patients with f ocally increased uptake, tumour recurrence (mean diameter: 2.4 cm; range 0. 4-6.5 cm) was found at initial endoscopy. In five patients recurrence was f ound during follow-up with a mean interval of 6.6 months. Seven patients ha d a false-positive study due to benign lesions or swallowing artefacts. In none of the patients with a normal PET study was tumour recurrence found du ring follow-up. The sensitivity and specificity of FDG dual-head PET were 1 00% and 71%, respectively. It is concluded that FDG dual-head PET is highly sensitive for the detection of local recurrence of laryngeal and hypophary ngeal carcinoma after radiotherapy. Some lesions were detected with a mean interval of 6.6 months before histological confirmation. In patients suspec ted of having recurrent laryngeal or hypopharyngeal cancer in whom FDG-PET is negative, endoscopy may be omitted for at least 6 months and possibly fo r up to 1 year.