Diagnostic Value Of¹⁸F-FDG PET/CT Combined Tumor Markers For Regional Lymph Node Metastasis In Patients With Non-small Cell Lung Cancer

Objective：To investigate the diagnostic value of18F-FDG PET/CT imagingcombined with serum tumor markers for regional lymph node metastasis ofpreoperative non-small cell lung cancer (NSCLC) patients.Materials and methods： To retrospectively analyze the18F-FDG PET/CTimaging and serum tumor markers level of75non-small cell lung cancer patientspreoperatively between June2010and June2013. All patients underwent lobectomyand corresponding draining lymph node dissection. All patients were confirmed bypathology examination: there were75lesions of primary tumor，45lesions had notregional lymph node metastasis, namely the primary tumor without lymph nodemetastasis group, another group was lymph node metastasis, contained30lesions,namely primary tumor with regional lymph node metastasis. PET/CT showed that130regional lymph nodes during the examination, which were divided into non-metastaticgroup79cases and metastatic group51cases, compared with pathologic examination.The maximum standardized uptake value (SUVmax), size of primary lung cancerlesions and the SUVmax, short diameter, CT value of lymph node were measuredand analyzed the location of the primary tumor (located within the one-third lungfield namely central lung cancer, others located two-third of the lung field weredefined as peripheral lung cancers). Analysis of preoperative serum tumor markers [contained carcinoembryonic antigen (CEA), cytokeratin-19fragment (Cyfra21-1),squamous cell carcinoma antigen (SCC)] levels of the patients were defined as follow,within the normal range marked as0, higher than the upper limit of the normal rangewithin one time marked as1,1to2times the count is recorded as2, by that analogy,but more than5times and beyond5were recorded as5.The relationship betweenregional lymph node metastasis and primary tumor SUVmax、 size and location,lymph node SUVmax、 short diameter and CT value, the level of serum tumormarkers were assessed by univariate and multivariate analysis. Univariate analysis wasperformed using t test and Mann-Whitney test, Binary logistic regression wasperformed for multivariate analysis, and establish the logistic regression models ofdiagnosis lymph node metastasis based on the results of multivariate analysis. Toacquire the optimal threshold value and the diagnosis efficacy in regional lymph nodemetastasis, respectively by Receiver Operating Characteristic Curve（ROC）analysis.In the last，using the chi-square test to compare PET/CT and logistic regression modelsin diagnosis accuracy of lymph node metastasis.Results：1. In the univariate analysis, primary tumor SUVmax（t=3.644，P=0.000）、size（t=3.290，P=0.002）、location（Z=-2.208，P=0.027）and the level of serum tumormarkers （Z=-3.554，P=0.000）were different in the two groups(primary tumor with orwithout regional lymph node metastasis);lymph node SUVmax（t=5.137，P=0.000）、short diameter（t=4.285，P=0.000）and CT value（t=-3.78，P=0.000）were differentin the two groups（lymph node non-metastatic group and metastatic group）.2. Logistic regression analysis showed that primary tumor maximum uptakevalue(SUVmax)（OR=1.172，P=0.043）、lymph node short diameter（OR=1.318，P=0.029）and the level of serum tumor markers（OR=7.293，P=0.010） wereindependent variables for lymph node metastasis.3. Furthermore, the AUC that logistic regression model、lymph node SUVmax andshort diameter diagnose regional lymph node metastasis were0．937±0．025(95％CI：0．888～0．987)、0.749±0.050(95％CI：0．650～0．848) and0.719±0.053(95％CI：0．615～0.823), respectively(P＜0.05);and the sensitivity and specificity were79.6%、95.3%;55.1%、81.4%;61.2%、79.1%, respectively. The optimal diagnostic cutoff value of lymph node SUVmax、lymph node size were4.75、8.75mm.4. Logistic model of regional lymph node metastasis diagnostic accuracy(88.5%)is higher than PET/CT imaging(75.4%)(χ2=7.51，P＜0.05).Conclusion：1.Regional lymph node metastasis correlated with primary tumor SUVmax、sizeand location, lymph node SUVmax、short diameter and CT value,and the level ofserum tumor markers.2.Primary tumorSUVmax、lymph node short diameter and the level of serumtumor markers were independent factors for regional lymph node metastasis.3. Logistic regression model combined of18F-FDG PET/CT imaging and tumormarker may improve the diagnostic value of NSCLC regional lymph node metastasis.