Diagnostic accuracy of 18F-2-deoxy-fluoro-D-glucose positron emission tomography for pN1 lymph nodes in patients with lung cancer.
BACKGROUND
Nodal status has been reported to be one of the most important factors affecting survival in patients with lung cancer. For determining treatment strategy, accurate evaluation of nodal status is expected.


OBJECTIVE
To evaluate the accuracy of (18)F-2-deoxy-fluoro-D-glucose (FDG) positron emission tomography (PET) for diagnosing nodal status in lung cancer patients with pathologically proven N1 (pN1) lymph node metastases, in comparison with that of computed tomography (CT).


METHODS
Nineteen pN1 patients with primary lung cancer undergoing preoperative CT and FDG-PET were investigated. The diagnosis was confirmed by surgery in all patients. Lymph nodes were considered to be positive when uptake higher than the surrounding mediastinum level was visually observed. Radiological and pathological correlation was investigated, and the association between FDG uptake and the size of metastatic nodes was evaluated.


RESULTS
Of the 19 pN1 patients, nodal stage determined by FDG-PET was cN0 in eight, cN1 in four, cN2 in six, and cN3 in one. Thus, FDG-PET provided correct N-staging in 21%, under-staging in 42%, and over-staging in 37%. FDG-PET could not depict pN1 lymph node in six (32%) of 19 patients. In two patients (11%), mild symmetrical hilar and mediastinal accumulation was found and considered as benign physiological uptake. In six patients (32%), the ipsilateral mediastinal uptake was depicted and diagnosed as cN2. One patient was diagnosed as cN3 because of FDG accumulation at the supraclavicular fossa. On CT, nodal staging was cN0 in nine, cN1 in six, and cN2 in four. CT staging was therefore correct in 32%, underestimated in 47%, and overestimated in 21%.


CONCLUSIONS
The diagnostic accuracy of FDG-PET (21%) was low and similar to that of CT (32%); under- and over-diagnosis were found in similar proportions. The limitation of FDG-PET should be recognized when nodal staging might alter the therapeutic strategy in patients with primary lung cancer.
Nakagawa
M
M
Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Japan. lmloltlolol@gmail.com
Hara
M
M
Sakurai
K
K
Ozawa
Y
Y
Mizuno
A
A
Tamaki
T
T
Nishio
M
M
Shibamoto
Y
Y
D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000601:surgery; D008207:Lymphatic Metastasis; D008223:Lymphoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18