Predictive Factors Of Lymph Node Metastasis And Risk Factors Of Postoperative Local (Regional) Recurrence In Non-small Cell Lung Cancer: A Meta-analysis

BackgroundThe morbidity and mortality of lung cancer take the first place in all malignancies,of which non-small cell lung cancer accounts for 85%.As for now,the first choice of treatment for early non-small cell lung cancer is still standard surgical resection,which means lobectomy plus systemic lymph node dissection or sampling.Recent retrospective research indicates that selective lymphadenectomy,a less invasive surgical approach of mediastinal lymph node dissection,may be an alternative approach for some patients with clinical stage ?-? non-small cell lung cancer.Occult lymph node metastases in early non-small cell lung cancer ranges from 14 to 19%,implying that more than 80%of patients whose preoperative lymph node negative,need to receive unnecessary lymph node dissection or sampling.Thus,it is important to predict pathological lymph node metastasis combining with patients'age,gender,tumor size,differentiation stage and other clinical pathological factors to select the most appropriate method for mediastinal lymph node dissection.However,large scale of prospective study are still in need to elaborate.The local recurrence rate of postoprerative non-small cell lung cancer is 20-50%,which is an vital factor for survival of postoperative patients.Previous study suggested that postoperative radiotherapy could increase local control but not survival benefit.Otherwise,a recent meta-analyzes pointed out that postoperative radiotherapy with a linear accelerator could reduce the risk of death.Relevant retrospective studies also indicated that postoperative radiotherapy may decrease local recurrence and achieve survival benefit in patients with stage IIIA-N2 non-small cell lung cancer.Nonetheless,there is still lack of large-scale prospective studies to confirm the role of postoperative radiotherapy under modern radiotherapy techniques.PurposeOur study aims to explore the predictive factors of lymph node metastasis and risk of postoperative local(regional)recurrence base on surgical pathology of early non-small cell lung cancer,as well as screening patients with occult lymph node metastasis and local(regional)recurrence.Moreover,it's also expected to guide the method of mediastinal lymph node dissection and provide evidence for further prospective researches.MethodsRelevant publications from Pubmed and Embase database were identified using the following search terms:NSCLC,surgery,lymph node,metastasis,recurrence,ect.Publications available in these databases up to April 2017 were analyzed,while related conference literature were also retrieved.According to the set inclusion/exclusion criteria,all documents were preliminarily screened by viewing titles and abstracts.After reading the full text,the selected documents that meet the standards were finally determined.Relevant information from final literatures were meta-analyzed by RevMan(V5.3)and forest map were also performed.And we conducted an analysis on risk factors of postoperative local(regional)recurrence in stage IIIA-N2 NSCLC.Postoperative patients which were pathologically confirmed lymph node metastasis were included in the analysis.SPSS 22.0 software was used for correlation analysis and COX regression analysis of relevant data such as age,gender,smoking and so on.ResultsA total of 2804 articles are retrieved and 15 are finally included,which are all retrospective studies.There were 11 articles about predictors of lymph node metastasis based on surgical pathology in 3229 patients and 4 articles about postoperative local(regional)risk factors for recurrence in 1775 patients.Meta-analysis showed that smoking index(BI)? 600,male,tumor diameter>2 cm,visceral pleural invasion,CEA level>5 ng/ml,higher SUVmax value,micropapillary pattern(?5%)and solid predominant were more relevant with postoperative pathology,which confirmed lymph node metastasis.Moreover,patients with wedge resection/segmentectomy,squamous cell carcinoma,visceral pleural invasion(VPI),lymphatic vessel invasion(LVI)have a higher risk of local(regional)recurrence.66 patients of our center were included in this retrospective analysis.Univariate and multivariate retrospective analyses showed that multi-station metastasis of mediastinal lymph node was independent risk factor of postoperative local(regional)recurrence.Conclusion:Smoking index(BI)?600,male,tumor diameter>2 cm,visceral pleural invasion,CEA level>5 ng/ml,higher SUVmax value,micropapillary pattern(?5%)and solid predominant are all predictive factors of lymph node metastasis based on surgical pathology.Meanwhile,wedge resection/segmentectomy,squamous cell carcinoma,visceral pleural invasion(VPI),lymphatic vessel invasion(LVI)multi-station metastasis of mediastinal lymph node are risk factors of local(regional)recurrence.The significance and clinical value of the above predictive or prognostic factors are yet to be further validated by large prospective studies.