Analysis Of The Role Of PET/CT In Lymph Node Diagnosis And Prognosis Of Lung Squamous Cell Carcinoma

Objective: Lung cancer is the leading cause of cancer death in men and women in the world, approximately 80–85% of cases are non-small cell lung carcinoma and which includes three main types: adenocarcinoma(40%), squamous cell carcinoma(20%-30%), and large cell carcinoma(10%). In which squamous cell carcinoma is more prone to lymph node metastasis, and lymph node metastasis in the development of the therapeutic regimen plays a decisive role. 18FDG-positron emission tomography(PET)/computed tomography(CT) has emerged as an accurate staging modality in lung cancer diagnosis. The primary goal of this study was the estimation of the diagnostic accuracy parameters of PET/CT in staging the hilar or mediastinum lymph nodes. Another aim of this study is to investigate the role of maximum standardized uptake value(SUVmax) on PET/CT in prognosis and its correlation with clinicopathological characteristics in resectable LSCC.Methods: One hundred and eighty-two resectable LSCC patients who underwent PET/CT imaging between May 2005 and October 2014 in Tianjin Medical University Cancer Institute and Hospital were enrolled into this retrospectively study. All the enrolled patients had undergone pulmonary resection with mediastinal lymph node dissection without preoperative chemotherapy or radiotherapy. To estimate the diagnostic accuracy parameters: positive predictive value(PPV), and negative predictive value(NPV) of PET/CT in staging the hilar or mediastinum lymph nodes in comparison with the reference standard of pathology. Survival outcomes were analyzed using the Kaplan-Meier method and multivariate Cox proportional hazards model. Correlation between SUVmax and clinicopathological factors was analysed using Pearson correlation analysis and Spearman rank correlation analysis.Results: When the individual patient is the unit of analysis, compared with histology, the sensitivity, specificity, PPV, and NPV of PET/CT were 48.7%, 88.8% for N1 lymph nodes, 50.0%, and 92.4% for N2 lymph nodes. PET / CT in peripheral lung cancer NPV for the diagnosis of lymph node N1 is higher than the central lung cancer group, the difference is statistically significant(P<0.001). The patients were divided into two groups on the basis of SUVmax 13.0, and patients with SUVmax more than13.0 had shorter median overall survival than patients less than 13.0 in univariate analysis(56 vs 87 months; P=0.022). There was correlation between SUVmax and, tumor size, TNM stage, neutrophil, NLR, hemoglobin, SCC levels(P < 0.05). Multivariate Cox analysis demonstrated that SUVmax(HR=1.714, 95%CI:1.021-2.876, P=0.042), TNM stage(HR=1.677, 95%CI: 1.231-2.284, P=0.001) were independent predictors for survival. Furthermore, univariate survival analysis showed significant difference by SUVmax in patients of stage ?(P=0.045).Conclusions: NPV in the diagnosis of N1 and N2 lymph nodes is higher, so the PET/CT for the diagnosis of lymph node negative with high reliability. SUVmax may be of importance prognostic factor independent of TNM stage, which is considerable for risk stratification in patients with TNM stage.Besides, there is correlation between SUVmax of primary tumor and clinicopathological characteristics.