Evaluation of head and neck cancer with F-18-FDG PET: a comparison with conventional methods

The aim of this study was to evaluate the usefulness of F-18-FDG PET in the diagnosis and staging of primary and recurrent malignant head and neck tum ours in comparison with conventional imaging methods [including ultrasonogr aphy, radiography, computed tomography (CT). and magnetic resonance imaging (MRI)], physical examination, panendoscopy and biopsies in clinical routin e. A total of 54 patients (13 female, 41 male, age 61.3 +/- 12 years) were investigated retrospectively. Three groups were formed. In group I, F-18-FD G PET was performed in 15 patients to detect unknown primary cancers. In gr oup II, 24 studies were obtained for preoperative staging of proven head an d neck cancer. In group III, F-18-FDG PET was used in 15 patients to monito r tumour recurrence after radiotherapy and/or chemotherapy. In all patients , imaging was obtained at 70 min after the intravenous administration of 18 0 MBq F-18-FDG. In 11 of the 15 patients in group I, the primary cancer cou ld be found with F-18-FDG, yielding a detection rate of 73.3%. In 4 of the 15 patients, CT findings were also suggestive of the primary cancer but wer e nonetheless equivocal. In these patients, F-18-FDG showed increased F-18- FDG uptake by the primary tumour, which was confirmed by histology. One pat ient had recurrence of breast carcinoma that could not be detected with F-1 8-FDG PET, but was detected by CT. In three cases, the primary cancer could not be found with any imaging method. Among the 24 patients in group II in vestigated for staging purposes, F-18-FDG PET detected a total of 13 local and three distant lymph node metastases, whereas the conventional imaging m ethods detected only nine local and one distant lymph node metastases. The results of F-18-FDG PET led to an upstaging in 5/24 (20.8%) patients. The c onventional imaging methods were false positive in 5/24 (20.8%). There was one false positive result using F-18-FDG PET. Among the 15 patients of grou p III with suspected recurrence after radiotherapy and/or chemotherapy, F-1 8-FDG was true positive in 7/15 (46.6%) and true negative in 4/15 (26.6%). The conventional imaging methods were true positive in 5/15 (33.3%) and tru e negative in 4/15 (26.6%). One false negative (6.6%) and three false posit ive findings (20%) on F-18-FDG PET were due to inflamed tissue. The convent ional imaging methods were false positive in three (20%) and false negative in three cases (20%). It is concluded that in comparison to conventional d iagnostic methods, F-18-FDG PET provides additional and clinically relevant information in the detection of primary and metastatic carcinomas as well as in the early detection of recurrent or persistent head and neck cancer a fter radiotherapy and/or chemotherapy. F-18-FDG PET should therefore be per formed early in clinical routine, usually before CT or MRI.