Impact of FDG-PET/CT for the Detection of Unknown Primary Tumours in Patients with Cervical Lymph Node Metastases

Abstract

Objective: Because the detection of the primary tumour is of importance to optimize the patient’s management and allows a targeted therapy, the performance of hybrid positron emission tomography–computed tomography (PET/CT) using fluorodeoxyglucose (FDG) in the detection of primary tumors and unrecognized metastases with cervical lymph node metastases were evaluated in a retrospective study. Material and Methods: Twenty patients with cervical lymph node metastases of unknown primary tumors underwent staging with FDG-PET/CT. All underwent head and neck examinations, computed tomography (CT), and/or magnetic resonance imaging (MRI), panendoscopies, and biopsies of head and neck mucosal sites. The diagnostic accuracy of FDG-PET/CT in detecting primary tumors was compared with that of histopathology and clinical follow-up. The ability of FDG-PET/CT to detect distant metastases was also tested. Results: PET/CT was positive with an increased FDG uptake suggesting the potential primary site in 45% of patients (9/20). PET/CT findings were true positive in 7, true negative in 10, false positive in 2, and false negative in 1 patients, resulting in a sensitivity of 87%, a specificity of 83%, an accuracy of 85%, a positive predictive value of 77% and a negative predictive value of 90%. Also, PET/CT showed distant metastases in seven patients. Conclusion: FDG-PET/CT can be successfully used for the identification of the primary site and distant metastases in patients with cervical lymph node metastases from an unknown primary cancer. Conflict of interest:None declared.

Diagnostic Accuracy of 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in the Evaluation of Carcinoma of Unknown Primary

“…In our cohort; lung, head and neck, and gastrointestinal tract malignancies were represented at equal frequencies (21.3%). This is also in line with meta-analyses in the literature ( 17 , 18 ). Small lesions in the head and neck, and the abdomen are difficult to localize as these are anatomically complicated regions.…”

Cáncer metastásico con primario desconocido. Una revisión

“…En estos pacientes puede ayudar a guiar la biopsia, determinar la extensión de la enfermedad, facilitar la planeación de la radioterapia y ayudar en el seguimiento de estos pacientes. Se ha encontrado que la TEP puede detectar el primario en un 30%-45% de los casos incluso cuando otros estudios imagenológicos no han sido conclusivos, otros estudios favorecen la TEP sobre la panendoscopia en este tipo de pacientes (40,42). Aparte de esta indicación, el rol de la TEP no es claro (16).…”