The value of 18F-FDG PET in the detection of stage M0 carcinoma of the nasopharynx.
Distant metastasis is an important issue for nasopharyngeal carcinoma (NPC). The potential value of PET using 18F-FDG has not been well defined. This prospective study investigated the impact of 18F-FDG PET in NPC patients with stage M0 disease.


METHODS
From April 2001 to June 2003, 140 NPC patients (118 primary and 22 primary recurrent) with stage M0 (negative results from chest radiography, liver sonography, and whole-body bone scanning) underwent 18F-FDG PET to check for distant metastases. Confirmatory MRI or CT was performed if any abnormal 18F-FDG uptake was found at distant sites. The distant lesion was confirmed pathologically, if feasible, and was followed up clinically and with imaging for at least 6 mo.


RESULTS
18F-FDG PET detected 26 true-positive metastatic sites in 18 (12.9%) of the 140 patients, among whom 14 had primary and 4 had recurrent tumors. The patient-based sensitivity and specificity of 18F-FDG PET for distant metastases were 100% and 86.9%, respectively. Mediastinal lymph nodes (n = 8) were the most common sites, followed by lung, liver, and bone (n = 5 each) and by other lymph nodes (n = 3). In patients with primary tumors, advanced nodal status (N2-3) was a statistically significant variable associated with development of distant metastases (P = 0.044). For recurrent NPC, neither age, sex, initial tumor stage, grade of differentiation, nor nodal stage showed a statistically significant difference between patients with and patients without distant metastases.


CONCLUSIONS
18F-FDG PET is valuable in avoiding aggressive locoregional radiotherapy in some NPC patients by the revelation of occult distant metastases, especially in patients with primary disease at a nodal stage of N2-3.
Yen
Tzu-Chen
TC
Department of Nuclear Medicine, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan. yen1110@adm.cgmh.org.tw
Chang
Joseph Tung-Chieh
JT
Ng
Shu-Hang
SH
Chang
Yu-Chen
YC
Chan
Sheng-Chieh
SC
Lin
Kun-Ju
KJ
Lin
Wuu-Jyh
WJ
Fu
Ying-Kai
YK
Lin
Chen-Yu
CY
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000556:secondary; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000556:secondary; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology*; D009367:Neoplasm Staging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016037:Single-Blind Method; D014915:Whole-Body Counting / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18