Inlfuence Of Visceral Pleural Invasion In Prognosis Of Postoperative Early Stage Non-small Cell Lung Cancer

Background:Lung cancer is the most common cancer with the highest mortalityworldwide. Jeopardized by smoking and environmental pollutions, China haswitnessed a4.6-fold increase in lung cancer mortality over the past threedecades. Lung cancer shows a higher incidence in males than in females, withan approximate ratio of2.3to1, and mostly occurs in people of40years or older.Of the two main types of lung cancer, i.e., non-small cell lung cancer (NSCLC)and small cell lung cancer (SCLC), NSCLC account for approximately85%. Forthose with early-stage NSCLC, radical resection is the first-choice treatment.However, due to varied prognosis observed in patients even after radicalresection, it is important to identify important prognostic factors for lung cancer,based on which, proper adjuvant or neo-adjuvant therapy may be selected tofurther improve the patients’ survival.For surgically managed NSCLC, the pathologic tumor, lymph node andmetastasis (TNM) staging system is the most important prognostic factor. Withinthe TNM system, visceral pleural invasion (VPI) has proven itself as anindependent poor prognostic factor over the past25years. Based on the seventhedition of the TNM staging system for lung cancer by International UnionAgainst Cancer (UICC) and American Joint Committee on Cancer (AJCC), VPIis defined as “invasion beyond the elastic layer (PL1) including invasion to thevisceral pleural surface (PL2)”. Tumors with VPI, regardless of its size,achieve a T2status. However, it is still under debate whether a tumor with a sizein between3-5cm and positive for VPI should be upgraded from T2a to T2b.In addition, the significance of VPI in the prognosis of early-stage NSCLC hasnot been systematically reviewed in China. In this study, we followed the definitions by the seventh edition of TNM classification, and retrospectivelyanalyzed the impact of VPI on the prognosis of261Chinese patients withearly-stage NSCLC (pathological stage I to II).Objective: To investigate the impact of visceral pleural invasion (VPI) on thepost-operative prognosis of patients with early-stage non-small cell lung cancer(NSCLC).Methods: Between Nov.2007and Nov.2011,261patients with pathologicalstage I to II NSCLC underwent radical resection in the First Affiliated Hospitalof Jilin University. The median follow-up time was36months. All the patientswere divided into VPI group and non-VPI group. There were130cases in VPIgroup and131cases in non-VPI group. The associations between VPI andprognosis of these patients were analyzed.X2test or fisher’s exact test was usedto analyze the categorical variables. Kaplan-Meier method was used to estimatedisease-free surviva（lDFS）and overall surviva（lOS）.COX proprotional hazardsmodel was used for the univariate and multivariate analyses.Results:1.Among all261patients examined, The one-year overall survival (OS)for patients with and without VPI was90.77%and93.13%, respectively, with nostatistical difference (P=0.075); the three-year and five-year OS for thesepatients was69.23%versus80.15%, and63.85%versus74.05%, respectively,showing statistical significance (P=0.040and0.049, respectively).2.VPI positivity has significantly negative impact on the five-year disease-freesurvival (DFS) of patients with T2a NSCLC without lymph node metastasis (P=0.024), but not on those with NSCLC of other sizes (P>0.05).3.There was no significant difference between pathologic stage T2a VPIpatients’ DFS and T2b patients’ DFS (regardless VPI, P=0.410, P=0.195).TheDFS for VPI patients with T2a NSCLC did not differ significantly from thosewith T2b NSCLC (regardless of their VPI status). 4.VPI significantly impacts the OS of only those with T1b NSCLC (P=0.024).5.VPI patients with T1b NSCLC showed similar OS as those with T2a NSCLC(regardless of their VPI status).6.Among all261patients examined, Univariate and multivariate analyses bothrevealed VPI as an independent prognostic factor for OS and DFS.Conclusion: VPI is an independent poor prognostic factor for patients withearly-stage NSCLC. In NSCLC, T1b with VPI should be treated with the samesurgical strategy as T2a, while T2a with VPI should be treated as for T2b.