ABSTRACT
Positron emission tomography with 18F-fluorodesoxyglucose (PET-FDG) could be used for the detection of the primary in cases of patient with carcinoma of an unknown primary site (CUP) and has been widely evaluated in this area. The most intensively explored situation is the form of cancer in patients presenting with cervical metastases of unknown primary. In such a situation, PET-FDG makes it possible to locate a primary in 33% of the patients and leads to a therapeutic modification for 35% of the patients. This examination should be carried out before the upper endoscopy, thus guiding the biopsies if possible. PET-FDG has been very little explored for patients presenting with metastases that are not cervical. On the basis of the small amount of data available, PET-FDG in this indication appears to localize the primary in 53% of cases, with an impact on the therapeutic care for 35% of the patients.
