Value of 18F-FDG PET/CT metabolic parameters of primary lesions for predicting occult lymph node metastasis in non-small cell lung cancer / 中华核医学与分子影像杂志

ABSTRACT

Objective:To investigate the predictive value of 18F-fluorodeoxyglucose (FDG) PET/CT metabolic parameters for occult lymph node metastasis (OLM) in non-small cell lung cancer (NSCLC). Methods:A total of 183 patients (72 males, 111 females; age (61.5±8.4) years) who underwent 18F-FDG PET/CT and preoperatively diagnosed with clinical N0 stage (cN0) in Third Affiliated Hospital of Soochow University from January 2013 to December 2018 were retrospectively enrolled. All patients underwent anatomical pulmonary resection with systematic lymph node dissections within 3 weeks after 18F-FDG PET/CT examinations. According to the presence or absence of lymph node metastasis, patients were divided into OLM positive (OLM+ ) group and OLM negative (OLM-) group. Parameters of primary lesions, such as the maximum diameter (D max), tumor sites, morphological features, maximum standardized uptake value (SUV max), mean standardized uptake value (SUV mean), metabolic total volume (MTV), total lesion glycolysis (TLG), tumor SUV max to liver SUV mean (TLR max), tumor TLG to liver SUV mean (TLR TLG) were analyzed. Mann-Whitney U test and χ2 test were used to compare the parameters between groups. Multivariable logistic regression was used to analyze the independent risk factors for OLM. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic value of different parameters. Results:Among 183 patients, 25 (13.7%, 25/183) of them were diagnosed as OLM. In OLM+ group, 46 lymph nodes were pathologically positive for metastasis, including 15 N1 disease and 31 N2 disease. D max (2.9(2.3, 3.7) vs 2.3(1.7, 2.8) cm), lobulation ((76.0%(19/25) vs 37.3%(59/158)), SUV max (11.1(7.9, 17.7) vs 4.7(2.3, 9.2)), TLG (41.5(10.2, 91.1) vs 15.6(6.5, 23.8) ml), TLR max (4.7(3.5, 7.6) vs 2.1(0.9, 4.0)) and TLR TLG (18.1(5.0, 44.3) vs 6.1(3.0, 11.4) ml) of the primary lesions in OLM+ group were significantly higher than those in OLM-group ( z values from -4.709 to -3.247, χ2=13.190, all P<0.05). Multivariable logistic regression analysis showed that TLR max (odds ratio ( OR)=15.145, 95% CI 3.381-67.830, P<0.001) and D max ( OR=3.220, 95% CI 1.192-8.701, P=0.021) were independent risk factors for OLM. TLR max yielded the highest area under curve (AUC; AUC=0.794) with the threshold of 3.12, and the sensitivity, specificity, accuracy, positive predictive value and negative predictive value for predicting OLM were 92.0%(23/25), 63.3%(100/158), 67.2%(123/183), 28.4%(23/81) and 98.0%(100/102), respectively. Conclusions:TLR max of tumor is the independent risk factor for OLM in NSCLC patients. TLR max can sensitively predict OLM preoperatively in patients with NSCLC.