The role of 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography in disseminated carcinoma of unknown primary site.
BACKGROUND
The authors conducted a comprehensive review of the efficacy of 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography (FDG-PET) in the detection of primary tumors in patients with disseminated carcinoma of unknown primary site.


METHODS
Ten studies (involving a total of 221 patients) tat were published between 1998 and 2006 were reviewed. Each study evaluated the role of FDG-PET in the detection of unknown primary tumors after a conventional diagnostic workup. Although 94% of patients had a single site of metastases, the studies otherwise were very heterogeneous in the studied population, study design, and additional diagnostic workup.


RESULTS
In 41% of patients, FDG-PET detected primary tumors that were not apparent after conventional workup. In this group of patients, the overall sensitivity, specificity, and accuracy rates of FDG-PET in detecting unknown primary tumors were 91.9%, 81.9%, and 80.5%, respectively. FDG-PET imaging also led to the detection of previously unrecognized metastases in 37% of patients. Lung cancers represented 59% of the detected tumors. FDG-PET had a notably high false-positive rate (58.3%) in tumors of the lower digestive tract. FDG-PET altered the clinical management in 34.7% of patients. Most of those patients (53%) received specific chemotherapy for lung and pancreatic cancers; whereas 12% received specific therapy for breast, ovarian, and prostate cancers; and 14% underwent surgery with curative intent.


CONCLUSIONS
FDG-PET was an efficient method for detecting primary tumors that were undetected by other modalities and was sensitive for the detection of previously unrecognized metastases. FDG-PET significantly changed clinical management in approximately one-third of the patients studied.
Sève
Pascal
P
Department of Internal Medicine, Hôtel Dieu, Hospices Civils de Lyon, Lyon, France. pascal.seve@chu-lyon.fr
Billotey
Claire
C
Broussolle
Christiane
C
Dumontet
Charles
C
Mackey
John R
JR
D003937:Diagnosis, Differential; D019788:Fluorodeoxyglucose F18; D006801:Humans; D009382:Neoplasms, Unknown Primary / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed / Q000379:methods*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18