Prospective study of 18FDG-PET in the detection and management of patients with lymph node metastases to the neck from an unknown primary tumor. Results from the DAHANCA-13 study.
BACKGROUND
The benefit of a complementary fluorodeoxyglucose-positron emission tomography (FDG-PET) scan to standard workup for carcinoma of unknown primary (CUP) and metastatic neck lesions was prospectively studied.


METHODS
Sixty-seven patients underwent standardized diagnostic workup according to national guidelines including panendoscopies, multiple mucosal biopsies, and diagnostic CT/MRI scans. Median follow-up was 40 months (range, 2-65 months).


RESULTS
In 60 eligible patients, FDG-PET indicated a primary tumor or metastatic disease in 30 patients (50%). Additional investigations confirmed a primary tumor in 18 patients: hypopharynx in 5, oropharynx in 5, nasopharynx in 2, lung in 1, axilla in 1, bone in 1, rectum in 1, as well as multiple metastatic lesions from CUP in 2 patients. In retrospect, MRI was able to detect 1 of the PET-detected primaries, leading to an overall detection rate of PET of 29% in CUP. A therapeutic change of treatment was made in 25% as a consequence of FDG-PET. PET before panendoscopy demonstrated fewer false-positive pathological foci.


CONCLUSIONS
FDG-PET is a valuable tool in addition to conventional extensive workup in CUP and neck metastases. Consequently, FDG-PET is now recommended as an early diagnostic modality in the workup of these patients.
Johansen
Jørgen
J
Department of Oncology, Odense University Hospital, Odense, Denmark. j.johansen@dadlnet.dk
Buus
Simon
S
Loft
Annika
A
Keiding
Susanne
S
Overgaard
Marie
M
Hansen
Hanne Sand
HS
Grau
Cai
C
Bundgaard
Troels
T
Kirkegaard
Jørgen
J
Overgaard
Jens
J
D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000628:therapy; D004724:Endoscopy; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy; D009382:Neoplasms, Unknown Primary; D049268:Positron-Emission Tomography; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D018714:Radiotherapy, Adjuvant; D012680:Sensitivity and Specificity
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18