Association of maximum standardized uptake value with occult mediastinal lymph node metastases in cN0 non-small cell lung cancer.
OBJECTIVE
The management of non-small cell lung cancer (NSCLC) relies on the tumour-node-metastasis (TNM) stage, and the treatment regimen differs based on the N status. Positron emission tomography-computed tomography (PET-CT) has emerged as a powerful imaging tool for the detection of various cancers with a relatively low false-negative rate. We explored predictors to identify false-negative N2 disease in PET-CT.


METHODS
A total of 284 consecutive cN0 patients with peripheral NSCLC who underwent PET-CT scans followed by curative intent resections were enrolled as a training set to identify predictors of occult N2 metastases by multivariable analysis. The accuracy and cut-off values for the predictors were calculated using a receiver operating characteristic curve. Clinical and pathological data were analysed retrospectively. An additional 151 patients were collected as a test set to validate the results, including the occult N2 rate and accuracy.


RESULTS
In total, 8.5% (24/284) PET-CT-diagnosed N0 NSCLC cases had pathologically diagnosed N2 metastases. The SUVmaxof the primary tumour was a unique independent risk factor for occult N2 NSCLC [P = 0.003, 95% confidence interval = 0.81-0.96, odds ratio (OR) = 0.88]. Occult N2 metastases occurred more frequently in the subcarinal (16/24) and right lower paratracheal lymph nodes (12/24). Accordingly, we divided the patients into two groups by SUVmax: the occult N2 rates in the SUVmaxof <2.6 and SUVmaxof ≥2.6 groups were 1.0% (1/100) and 12.5% (23/184), respectively (P = 0.001). In the test set, the occult N2 incidence rate was 9.3% (14/151), with the highest rates occurring in the subcarinal (9/14) and right lower paratracheal lymph nodes (6/14). In the two groups defined by SUVmax, the occult N2 rates were 4% (2/50) and 11.9% (12/101), respectively.


CONCLUSIONS
The SUVmaxof the primary tumour was an independent risk factor for occult N2 metastases in NSCLC patients diagnosed as clinical N0 by PET-CT. SUVmaxof ≥2.6 of the primary tumour may indicate the risk of N2 metastases, and invasive mediastinal staging techniques or comprehensive therapy should not be ignored in these patients.
Guangdong Lung Cancer Institute, Guangdong General Hospital & Guangdong Academy of Medical Science, Guangzhou, China.|Guangdong Cardiovascular Institute, Guangzhou, China.
Jun-Tao
JT
Lin
Guangdong Lung Cancer Institute, Guangdong General Hospital & Guangdong Academy of Medical Science, Guangzhou, China.
Xue-Ning
XN
Yang
Guangdong Lung Cancer Institute, Guangdong General Hospital & Guangdong Academy of Medical Science, Guangzhou, China.
Wen-Zhao
WZ
Zhong
Guangdong Lung Cancer Institute, Guangdong General Hospital & Guangdong Academy of Medical Science, Guangzhou, China.
Ri-Qiang
RQ
Liao
Guangdong Lung Cancer Institute, Guangdong General Hospital & Guangdong Academy of Medical Science, Guangzhou, China.
Song
S
Dong
Guangdong Lung Cancer Institute, Guangdong General Hospital & Guangdong Academy of Medical Science, Guangzhou, China.
Qiang
Q
Nie
Second Clinical Medical College, Southern Medical University, Guangzhou, China.
Si-Xian
SX
Weng
Second Clinical Medical College, Southern Medical University, Guangzhou, China.
Xiao-Jing
XJ
Fang
Second Clinical Medical College, Southern Medical University, Guangzhou, China.
Jun-Yi
JY
Zheng
Guangdong Lung Cancer Institute, Guangdong General Hospital & Guangdong Academy of Medical Science, Guangzhou, China syylwu@live.cn.
Yi-Long
YL
Wu
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008482:Mediastinum; D008875:Middle Aged; D009367:Neoplasm Staging; D000072078:Positron Emission Tomography Computed Tomography; D011300:Preoperative Care / Q000379:methods; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity
18F-fluorodeoxyglucose PET–CT; Mediastinal staging; N2; Non-small cell lung cancer; SUVmax