Whole body 18F-FDG PET/CT imaging in the detection of primary tumours in patients with a metastatic carcinoma of unknown origin.
OBJECTIVE
The aim of this study was to evaluate the role of whole body 18F-FDG PET/CT imaging in the detection of primary tumors in patients with a metastatic cancer from an unknown primary site.


METHODS
The study population consisted of 43 patients with a biopsy proven metastatic disease, negative conventional diagnostic procedures (including CT/MRI/endoscopic procedures) and a whole body 18F-FDG PET/CT examination. Patients' records were retrospectively analyzed. According to the final pathologic diagnoses, rate of detection of the primary tumor site was determined. Additionally, overall patient survival was calculated to evaluate the prognostic value of 18F-FDG PET/CT findings.


RESULTS
A primary tumor site was shown by 18F-FDG PET/CT in 24 patients (24/43; 55.8%). In 18 patients 18F-FDG PET/CT scans were negative (18/43; 41.8%). In a patient with an adenocarcinoma metastasis 18F-FDG PET/CT was falsely positive for an inflammatory lesion in the lung. Among the 18F-FDG PET/CT positive and negative groups median overall survival was not significantly different (log-rank p=0.573).


CONCLUSIONS
Whole body 18F-FDG PET/CT imaging has a high rate of detection of a primary tumor in patients with a carcinoma of unknown origin.
Kaya
Ali Osman
AO
Gazi University, School of Medicine, Department of Medical Oncology, Turkey.
Coskun
Ugur
U
Unlu
Mustafa
M
Akdemir
Umit Ozgur
UO
Ozdemir
Nuriye Yildirim
NY
Zengin
Nurullah
N
Benekli
Mustafa
M
Yildiz
Ramazan
R
Yaman
Emel
E
Ozturk
Banu
B
Gumus
Mahmut
M
Uner
Aytug
A
Yamac
Deniz
D
Ucgul
Emel
E
Buyukberber
Suleyman
S
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000401:mortality / Q000556:secondary; D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000556:secondary; D002423:Cause of Death; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000556:secondary; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D009382:Neoplasms, Unknown Primary / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D011336:Probability; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000556:secondary; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods; D051598:Whole Body Imaging / Q000379:methods
D019788:Fluorodeoxyglucose F18