Correlation Of PET/CT SUV_max With Infiltration Of Immune Cells In Patients With Non-small Cell Lung Cancer And Its Clinical Significance

Objective: Lung cancer is the most common cancer in the world,and its morbidity and mortality are among the top of malignant tumor.NSCLC accounts for about 80-90% of all the lung cancers,and most patients have had distant metastases at the time of diagnosis.Although the survival rate of patients with NSCLC was significantly improved by combined treatment with chemotherapy,radiotherapy and biotherapy,the 5-year survival rate of patients was still poor.The immune status of tumor microenvironment is of great significance to the occurrence,development and prognosis of cancer.However,there are many restrictions in the clinical material of the primary tumor.18FDG-positron emission tomography(PET)/computed tomography(CT)has been widely used as a noninvasive approach to clinical diagnosis,treatment and prognosis of NSCLC.The aim of this study was to access the relationship between 18F-FDG maximum standard uptake value(SUVmax)and immune cells infiltration in non-small cell lung cancer(NSCLC)patients,and explore its significance in NSCLC patients’ treatment and prognosis.Methods: From April 2008 to August 2014,a total of 119 cases patients with NSCLC(32 cases of squamous cell carcinoma,87 cases of adenocarcinoma)who underwent primary tumor resection and PET/CT imaging at Tianjin Medical University Cancer Institute and Hospital were collected and retrospectively analyzed.The infiltration of CD3+tumor infiltrating lymphocytes(TILs),CD8+TILs,CD68+tumor-associated macrophages(TAMs),CD163+TAMs and CD11c+dendritic cells(DCs)was determinded by immunohistochemistry.Correlation between infiltration of immune cells and clinicopathological parameters were analysed using the x2 test.Correlation between infiltration of immune cells and SUVmax was analyzed using Pearson correlation analysis.Survival outcomes were analyzed using the Kaplan-Meier method and multivariate Cox proportional hazards model.Result:1.The immune cell subsets was observed with different degrees of infiltration at primary tumor in the NSCLC.Which mainly manifested as cell membrane or cytoplasm appears brown particles.Significant associations between infiltration of CD3+TILs and TNM stage and lymph node metastasis were identified.The infiltration of CD8+TILs was significantly correlated with lymph node metastasis and prognosis.The infiltration of CD11c+DCs was associated with histological type lymph node metastasis.2.There was remarkably positive correlation between PET/CT SUVmax and infiltration of CD8+TILs(r=0.332;P<0.001)and CD163+TAMs(r=0.223;P=0.015).However,there is no significant correlation between SUVmax and infiltration of CD3+TILs,CD68+TAMs and CD11c+DCs.In addition,the correlation analysis of the infiltration between immune subpopulations was not statistically significant.3.Univariate analysis showed that TNM staging,SUVmax,tumor size and infiltration of CD163+TAMs and CD11c+DCs were correlated with prognosis of patients.Multivariate analysis showed that TNM stage and SUVmax were independent prognostic factors.Conclusion: The present study shows a direct association between metabolic parameters SUVmax and the infiltration of immune cells,suggesting a potential role of 18F-FDG PET/CT to indirectly reflect the immune status of the tumor microenvironment,which also has a crucial reference value for prognosis and selecting NSCLC patient candidates to receive timely and effective intervention.But the specific biological mechanism needs further exploration.