Comparison Of Clinical Outcomes Of Different Types Of Pulmonary Segmentectomy Based On Propensity Score Matching Under Minimally Invasive Techniques

Background:In the surgical treatment of early-stage non-small cell lung cancer(NSCLC)with a diameter of no more than 2cm,segmentectomy has been shown to have oncological outcomes no worse than lobectomy and is currently being gradually promoted.Pulmonary segmentectomy is usually divided into typical and atypical segmentectomy,depending on the complexity of intraoperative establishment of an intersegmental-plane.Atypical segmental resection requires the establishment of multiple intersegmental planes during the operation,which increases the complexity and difficulty of the operation,the corresponding operation time and the potential risk of postoperative complications.With the development of minimally invasive technologies,minimally invasive surgeries,such as video-assisted thoracoscopic surgery(VATS)and robot-assisted thoracoscopic surgery(RATS),have achieved significant results in the treatment of early NSCLC.Due to its advantages such as low surgical trauma,quick postoperative recovery and stable therapeutic effect,the feasibility of segmentectomy including atypical lung segments that are difficult to operate is increased.However,few studies have compared the roles of VATS and RATS in different types of segmentectomy.Therefore,the aim of this study is to compare the perioperative and long-term outcomes of different types of segmental NSCLC treated with minimally invasive techniques such as VATS and RATS based on Propensity Score Matching(PSM),in order to evaluate the safety and feasibility of typical and atypical segmentectomy,as well as the safety and feasibility of RATS and VATS in different types of segmentectomy,and provide reference for the selection of surgical options for early-stage NSCLC.Method:This study retrospectively reviewed all patients who underwent VATS or RATS segmentectomy for non-small cell lung cancer(NSCLC)at the Department of Thoracic Surgery of Qingdao University Affiliated Hospital between July 2014 and December 2019.After excluding patients who did not meet the inclusion criteria,all eligible patients were divided into typical and atypical segment groups,and then subdivided into VATS segmentectomy and RATS segmentectomy subgroups according to the surgical approach.Between-group comparisons were based on PSM of baseline data.The main retrospective indicators included operation time,intraoperative blood loss,lymph node resection,postoperative complications,postoperative drainage time,and postoperative hospital stay.In addition,the disease free survival(DFS)and overall survival(OS)of the patients were analyzed.Kaplan-Meier survival analysis and survival curve were drawn,and Log-rank test was used to compare the survival rate between groups.Statistical analysis was performed by SPSS 25.0 and R 4.1.3,and p<0.05 indicated that the difference was statistically significant.Result:A total of 538 patients with early-stage NSCLC who underwent VATS or RATS segmentectomy were enrolled in this study.The follow-up time was 32-101 months,with a median follow-up time of 49.5 months.After PSM to balance the baseline data distribution levels,a total of 238 pairs of patients with typical and atypical lung segments were obtained.Compared to the typical lung segment group,the non-typical lung segment group had a longer operation time(p=0.018),while there was no statistically significant difference in intraoperative blood loss,number of resected lymph node groups,N2 lymph node groups,total number of lymph nodes,incidence of postoperative complications(including air leakage,lung infection,and atrial fibrillation),drainage status(including drainage volume and drainage tube duration),and length of postoperative hospital stay(p>0.05),long-term results showed that there were no significant differences in disease-free survival and overall survival between the two groups(p>0.05).After matching,a total of 125 pairs of patients who underwent VATS pulmonary segmentectomy and RATS pulmonary segmentectomy were obtained,with the RATS group having more resected lymph node groups,N2 lymph node groups,and total number of lymph nodes than the VATS group(p<0.05),while there was no statistically significant difference in operation time,intraoperative blood loss,incidence of postoperative complications,drainage status,and length of postoperative hospital stay(p>0.05),long-term results showed that there were no significant differences in disease-free survival and overall survival between the two groups(p>0.05).After matching in the typical lung segment group,a total of 44 pairs of patients who underwent VATS pulmonary segmentectomy and RATS pulmonary segmentectomy were obtained,with the RATS subgroup having more resected lymph node groups,N2 lymph node groups,and total number of lymph nodes than the VATS subgroup(p<0.05),while there was no statistically significant difference in operation time,intraoperative blood loss,incidence of postoperative complications,drainage status,and length of postoperative hospital stay between the two subgroups(p>0.05),long-term results showed that there were no significant differences in disease-free survival and overall survival between the two subgroups(p>0.05).After matching in the non-typical lung segment group,a total of 77 pairs of patients who underwent VATS pulmonary segmentectomy and RATS pulmonary segmentectomy were obtained,with the RATS subgroup having more resected lymph node groups,N2 lymph node groups,and total number of lymph nodes than the VATS subgroup(p<0.05),while there was no statistically significant difference in operation time,intraoperative blood loss,incidence of postoperative complications,drainage status,and length of postoperative hospital stay between the two subgroups(p>0.05),long-term results showed that there were no significant differences in disease-free survival and overall survival between the two subgroups(p>0.05).None of the patients died during the follow-up.Conclusion:Therefore,in conclusion,minimally invasive techniques-assisted pulmonary segmentectomy have similar perioperative and long-term prognosis results for NSCLC treatment,regardless of whether the resection is performed in typical or atypical segments.Non-typical segmentectomy has a longer operation time than typical segmentectomy,but there is no significant difference in perioperative outcomes and long-term prognosis.Among different types of segmentectomy,RATS pulmonary segmentectomy has similar perioperative outcomes and long-term prognosis as VATS pulmonary segmentectomy,but RATS is more advantageous for lymph node dissection.