Analysis Of Prognosis And Technique During Segmentectomy For Early-stage Non-small Cell Lung Cancer

Background and Objectives:Whether segmentectomy can be used to treat radiologically determined pure solid or solid-dominant lung cancer remains controversial owing to the invasive pathologic characteristics of these tumors despite their small size.The first part of this article is to compared the oncologic outcomes after lobectomy and segmentectomy regarding relapse-free survival(RFS)and overall survival(OS)in patients with radiologically determined pure solid or solid-dominant clinical stage IA non-small cell lung cancer(NSCLC)by performing a meta-analysis.Owing to the fact that the segmental bronchi and vessels are commonly variable and complicated,it is difficult to correctly identify them.Misidentification of the segmental anatomy could result in the failure of segmentectomy and conversion to the other surgical procedures(such as bisegmentectomy or lobectomy).As a result,we summarized a novel method named"two-way identification" to identify the target segmental vessels and bronchi by exposing the adjacent segmental anatomy during uniportal video-assisted thoracoscopic(VATS)segmentectomy.So the second part of this article is to evaluate the safety and technical feasibility of "two-way identification".Methods:The first part:A literature search was performed in the MEDLINE,EMBASE,and Cochrane Central databases for information from the date of database inception to March 2019.Studies were selected according to predefined eligibility criteria.The hazard ratio(HR)and associated 95%confidence interval(CI)were extracted or calculated as the outcome measure for data combining.The second part:Perioperative data of 106 patients who applied this method of two-way identification during video-assisted thoracoscopic anatomic segmentectomy between September 2017 and September 2019 are retrospectively analyzed.Two-way identification refers to dissect the hilar structures adequately to the extent of visualization of the target and adjacent segmental vessels or bronchi firstly.And then the target segmental vessels and bronchi were preliminarily determined according to their running direction,followed by further confirmation by exposing the adjacent segmental anatomy.Results:The first part:Seven eligible studies published between 2014 and 2018 enrolling 1428 patients were included in the current meta-analysis.Compared with lobectomy,segmentectomy had a significant inferior on the RFS of radiologically determined pure solid or solid-dominant clinical stage IA(≤3 cm)NSCLC patients(combined HR:1.46;95%CI,1.05-2.03;P=0.024)and the subgroup analysis of the tumor with a diameter of 2 cm showed a higher risk of segmentectomy had a higher risk(HR=1.8;95%CI,1.19-2.70;P=0.005).There were no significant differences on the OS of these patients(HR:1.52;95%CI,0.95-2.43;P=0.08).The second part:Of all 106 patients,two patients were converted to lobectomy due to bleeding for technical faux pas and there was no case converted to lobectomy or thoracotomy for misidentification of segmental anatomical structures.The operation time was 70-160 min(mean,105 min),and the intraoperative blood loss was 20-140 ml(mean,56 ml).The postoperative thoracic drainage time was 1-7d(mean,3.5d),and the postoperative hospital stay was 3-14d(median,5d).Postoperative complications included air leakage(>5 days)in 5 cases,hemoptysis in 2 cases,atelectasis in 4 cases,pleural effusion in 5 cases,pneumonia in 3 cases,and arrhythmia in 2 cases,all of which were controlled by conservative treatment.There was no perioperative deathConclusion:The first part:Segmentectomy leads to lower survival than lobectomy for clinical stage IA NSCLC patients with radiologically determined pure solid or solid-dominant tumors.Moreover,applying lobectomy to clinical stage IA(≤3 cm)NSCLC patients with radiologically determined pure solid or solid-dominant tumors(≤2 cm)could lead to an even bigger survival advantage.However,there are some limitations in the present study,and more evidence is needed to support the conclusion.The second part:The method of two-way identification allowed complete uniportal VATS segmentectomy to be performed successfully and ensure the accurate identification and dissection of the target segmental anatomy.Moreover,the method make the operation simple and easy,and make the whole procedure organized and programmed,suitable for popularity in clinical application.