Diagnosis Value Of ¹⁸F-FDG PET/CT For Lymph Node Metastasis In Non-small Cell Lung Cancer

ObjectiveTo discuss the diagnostic value of the metabolic parameters associated with 18F-FDG PET/CT non-small cell lung cancer lesions on lymph node metastasis。MethodsWe retrospectively analyzed preoperative ¹⁸F-FDG PET/CT images of236 patients with NSCLC.Inclusion criteria:1.18F-FDG PET/CT examination found solitary high metabolic lesions in the lung,and no distant metastasis;2.Postoperative pathology confirmed as non-small cell lung cancer with or without lymph node metastasis.3.PET/CT scan and preoperative radiotherapy,chemotherapy and other related treatments were not performed;4.The time interval between 18F-FDG PET/CT scan and surgery is not more than 2 weeks.Exclusion criteria:except for the history of other tumors.According to whether FDG uptake found in lymph nodes by 18F-FDG PET/CT scan,all the cases were divided into two groups,which 154 cases in the negative group and 82 cases in the positive group.The negative group is divided into a true negative group and a false negative group according to the results of the pathological examination,and the positive group is divided into a benign group and a malignant group according to the results of the pathological examination.The related parameters analyses of the primary tumors were done in the negative group,The related parameters analyses of the lymph nodes were done in the positive group.Finally,generate nomogram based on prediction model results using R software.Finally,based on the ROC curve,the area under the curve and the diagnostic efficiency of the two sets of parameters and the prediction model are obtained.ResultThe lymph nodes phases were explored in all the 236 cases.145 cases are N0 phase,22 cases are N1 phase,69 cases are N2 phase。Univariate analysis showed that short diameter,density and SUVmax value of lymph node,lymph node/liver SUV value ratio,lymph node/mediastinum SUV value ratio,primary tumor location,presence or absence of calcification,and patient age were statistically different between benign and malignant lymph nodes.Multivariate analysis showed that short diameter,and density of lymph node,presence or absence of calcification,and lymph node/liver SUV value ratio were the predictors of lymph nodes metastasis.The sensitivity,specificity,positive predictive value,negative predictive value,positive likelihood ratio and negative likelihood ratio of the prediction model were respectively as 0.685、0.864、0.833、0.75、5.53、0.364.ROC curve analysis showed that the area under the curve of the lymph node short diameter,lymph node/liver SUV ratio,density,calcification and the model were 0.694,0.669,0.341,0.601,0.812,respectively.In negative group,the patient’s age,primary tumor SUVmax value,primary tumor/liver SUV value ratio,primary tumor/mediastinum SUV value ratio,and maximum diameter of primary tumor were statistically significant between false negative and true negative groups,and there was no statistically significant difference in gender and primary tumor location between these two groups.Multivariate analysis found that the primary tumor SUVmax and maximum diameter of primary leision were the predictive factors of occult lymph node metastases,the sensitivity,specificity,positive predictive value,negative predictive value,positive likelihood ratio and negative likelihood ratio of the prediction model were respectively 0.625、0.842、0.581、0.865、3.959、0.445.ROC curve analysis showed that the area under the curve of maximum diameter of primary leision and the primary tumor SUVmax were 0.691、0.722,0.749。ConclusionThe short diameter,density,calcification state of lymph node and lymph node/liver SUV ratio can be as good predictors for lymph nodes metastasis.The maximum diameter of the primary lesion and the primary lesion SUVmax are independent risk factors for occult lymph node metastasis.Both prediction models have better diagnostic efficiency and higher specificity,which can help clinically stratify prediction based on the presence or absence of FDG uptake of lymph nodes and determine the presence or absence of lymph node metastasis.At the same time,combined with the nomogram to predict the risk of lymph node metastasis intuitively and accurately,so as to guide clinical precise treatment.