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.
Highlights
Carcinomas of unknown primary are the seventh most frequent type of cancer in the world (1) In about 2-10% of all newly diagnosed biopsy-confirmed malignancies, the site of origin is not identified by routine clinical workup and they are categorized as carcinoma of unknown primary cancer
The usual diagnostic work-up consists of a physical examination, fiber optic laryngoscopy and nasopharyngoscopy, conventional imaging, i.e. computed tomography (CT) and/or magnetic resonance imaging (MRI), panendoscopy with biopsies directed on the suspected primary tumour sites or randomized in the most frequent sites of primary tumour, and sometimes tonsillectomy if the metastatic lymph nodes are located in the upper and middle cervical levels, especially in the case of squamous cell carcinoma (SCC)
Because many neoplasms have higher glycolytic activity than normal tissue, primary and metastatic tumors show greater uptake of the glucose analog FDG, and appear as hot spots on PET images (5). The aim of this retrospective study was to evaluate the performances of FDG positron emission tomography–computed tomography (PET/CT) in patients with cervical lymph nodes metastases from cancer of unknown primary concerning the detection of the primary tumour and/or distant lesions
Summary
Carcinomas of unknown primary are the seventh most frequent type of cancer in the world (1) In about 2-10% of all newly diagnosed biopsy-confirmed malignancies, the site of origin is not identified by routine clinical workup and they are categorized as carcinoma of unknown primary cancer. The usual diagnostic work-up consists of a physical examination, fiber optic laryngoscopy and nasopharyngoscopy, conventional imaging, i.e. computed tomography (CT) and/or magnetic resonance imaging (MRI), panendoscopy with biopsies directed on the suspected primary tumour sites or randomized in the most frequent sites of primary tumour, and sometimes tonsillectomy if the metastatic lymph nodes are located in the upper and middle cervical levels, especially in the case of SCC. Because many neoplasms have higher glycolytic activity than normal tissue, primary and metastatic tumors show greater uptake of the glucose analog FDG, and appear as hot spots on PET images (5) The aim of this retrospective study was to evaluate the performances of FDG PET/CT in patients with cervical lymph nodes metastases from cancer of unknown primary concerning the detection of the primary tumour and/or distant lesions
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