Relations Between Visceral Pleural Invasion And Clinicopathological Characteristics And Prognosis Of Lung Adenocarcinoma With Tumor Diameter?3cm

[Objective]To explore the relation between visceral pleural invasion(VPI)and other clinicopathological characteristics of lung adenocarcinoma with maximum diameter?3cm;to evaluate the impact of different levels of VPI on the survival of patients with small tumors;to explore the value of VPI as a prognostic factor;and to further clarify the role of elastic fiber staining in the diagnosis of VPI.[Materials and Methods]Conducted retrospective analysis of clinicopathological data of 231 cases of lung adenocarcinomas with maximum diameter?3cm that were completely resected and lymph nodes were systematically removed,and there were no distant organ metastasis.Read past tissue sections and re-diagnosed according to the World Health Organization's Lung Cancer Histology Classification Criteria 2015.Selected tissue wax blocks which might be invaded by the tumor or were close to the visceral pleura.Stained new sections with hematoxylin-eosin,Victoria blue,and Ki-67 immunohistochemisty.Classified VPI according to Modified Hammar Classification and obtained Ki-67 proliferation index(PI)through cell counting.The cut-off value of Ki-67 PI was determined by using the receiver operating characteristic(ROC)curve.Evaluated the relation between other clinicopathological characteristics of lung adenocarcinoma and VPI classes by using one-way ANOVA,rank sum test and Spearman rank correlation coefficient.Taking progression-free survival(PFS)and overall survival(OS)as the main research end point,single factor survival analysis was performed by Kaplan-Meier method;and the Cox proportional hazards model was used to explore the independent risk factors for prognosis.[Results]In 231 cases of patients suffered from lung adenocarcinoma with maximum tumor diameter?3cm,70 cases(30.3%)were associated with VPI.Among them,61 cases(26.4%)were PL1,9 cases(3.9%)were PL2.No VPI(PLO)were found in the remaining 161 cases(69.7%).The tumor size(rs=0.224,P=0.001),major histological types(P=0.008),histological grading(rs=0.264,P<0.001),solid component(rs=0.226,P<=0.001),micropapillary component(rs=0.173,P=0.028),Ki-67 PI(rs=0.187,P=0.004),N staging(rs=0.308,P<0.001)and TNM staging(rs=0.650,P<0.001)were significantly correlated with VPI classification.Single factor survival analysis showed that PFS and OS of patients with VPI were significantly shorter than those without VPI(P<0.001);and there was significant difference of PFS and OS between different VPI groups(P<0.001).Multivariate Cox's regression analysis showed:with regard to lung adenocarcinoma with maximum tumor diameter<3cm,? VPI classification was an independent risk factor for OS(P=0.038),but not an independent predictor of PFS(P=0.052);? VPI was not an independent factor in the prognosis of patients(PFS:P=0.248,OS:P 0.172);?There was no significant difference between PL1 and PLO in patients' survival.PL1 was not an independent prognostic factor(PFS:P=0.616,OS:P=0.856);? The impact of PL2 on the survival of patients was significantly different from that of PL1.PL2 was an independent risk factor for PFS(P=0.003)and OS(P=0.009)of patients with VPI;? PL2 is an independent risk factor for PFS(P=0.007),but not an independent predictor of OS(P=0.052).[Conclusions]In the lung adenocarcinoma with the maximum diameter?3cm,VPI and its invasion are significantly associated with poor prognosis,but PL1 or VPI(PL1 and PL2)is not an independent prognostic factor of patients;and only PL2 is an independent risk factor for PFS of patients.Therefore,in the diagnosis of patients with small lung adenocarcinoma,it may not be necessary to use elastic fiber staining to distinguish between PLO and PL1,and it requires future study and discussion whether the definition of VPI need to be modified.