Role of whole body positron emission tomography/computed tomography scan with 18F-fluorodeoxyglucose in patients with biopsy proven tumor metastases from unknown primary site.
OBJECTIVE
The aim of this study was to evaluate the role of whole body PET/CT scan with (18)F-fluorodeoxyglucose (FDG) in the detection of the primary tumor in patients with metastatic cancer from unknown primary origin (CUP syndrome).


METHODS
Sixty-eight consecutive patients, with CUP syndrome (39 lymph nodes, 29 visceral biopsy proven tumor metastases), underwent a whole-body FDG-PET/CT study. All enrolled patients were unsuccessfully studied, within the previous month, with physical examination, laboratory tests and conventional diagnostic procedures. All the pathological findings identified at PET/CT scan and suspected for primaries, were further investigated. After PET study, the minimum follow-up period for the inclusion in the studied population was 3 months.


RESULTS
The primary tumor site was correctly identified by FDG-PET/CT in 24 patients (24/68, 35.3%): lung (n=9), rino/oro-pharynx (n=6), pancreas (n=5), colon (n=2), uterus (n=2). In 5 cases, FDG-PET scan did not identify a primary pathological focus, which was subsequently detected by other diagnostic methods within 3 months. In 39 patients (39/68, 57.4%), the primary tumor site was not localized. However, in 9 of them, FDG-PET/CT scan identified further unexpected metastases, modifying the stage of disease. Overall, the following oncological treatment was influenced by the PET scan, in a total of 33 patients (33/68, 48.5%).


CONCLUSIONS
Our data strongly support the diagnostic contribution of whole body FDG-PET/CT scan in the evaluation of patients with CUP syndrome and suggest its use in an early phase of the diagnostic iter to optimize patient management.
Pelosi
E
E
University Nuclear Medicine Service, ASO S. Giovanni Battista, Turin, Italy.
Pennone
M
M
Deandreis
D
D
Douroukas
A
A
Mancini
M
M
Bisi
G
G
D000328:Adult; D000368:Aged; D001706:Biopsy / Q000706:statistics & numerical data; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis* / Q000453:epidemiology*; D049268:Positron-Emission Tomography / Q000706:statistics & numerical data*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013382:Subtraction Technique / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D051598:Whole Body Imaging / Q000706:statistics & numerical data*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18