Postoperative Radiation Therapy (PORT) In Non-small Cell Lung Cancer(NSCLC)

PART 1 PORT for Resected Stage ?A(N2)NSCLC in Different Time Periods: A Population-Based Time-Trend Study Using SEER DatabasePurpose: The value of postoperative radiotherapy(PORT)for resected stage ?A(N2)non-small-cell lung cancer(NSCLC)is controversial with few studies focusing on whether PORT always plays a part in clinical practice and generates benefits to patients across different time periods.We investigated this issue using the Surveillance,Epidemiology,and End Results Database(SEER)and assessed the temporal trends spanning 27 years.Methods: Within SEER,we selected stage ?A-N2 NSCLC patients who underwent a lobectomy or pneumonectomy and coded as receiving PORT or never receiving radiotherapy over three time periods: 1988 to 1996,1997 to 2005,2006 to 2014.For each period,survival analyses were performed and propensity score matching(PSM)was used to balance the baseline.Results: 45.4% of 5568 eligible patients received PORT.The yearly PORT use rates varied largely from 27.8% to 74.4%.Overall survival(OS)was distinctly improved over the periods.The application of PORT had significant impact on survival only in period 1 and 3.In subgroup analysis,the OS benefit of PORT was significant in each period in patients with 50% or more lymph node ratio(LNR)both before(hazard ratios,and P values of 0.647,P=.002;0.804,P=.008;0.721,P<.001 for period 1,2,3,respectively)and after PSM(0.642,P=.006;0.785,P=.004;0.748,P=.003 for period 1,2,3,respectively).Conclusions: The benefits of PORT are lasting and stable throughout the years in patients with LNR of 50% or more.This might provide a clue on proper patient selection for PORT application.PART 2 Cardiac Mortality in Resected Stage IIIA(N2)NSCLC Patients: A Competing Risk Analysis Using SEER DatabasePurpose: To investigated the cumulative incidences of cardiac specific mortality(CSM)over time periods and explored whether postoperative radiotherapy(PORT)would increase risks of CSM in resected stage IIIA(N2)non-small-cell lung cancer(NSCLC)patients.Methods: The Surveillance,Epidemiology,and End Results database was queried for stage IIIA(N2)NSCLC patients who underwent a lobectomy or pneumonectomy and received PORT or observation over two time periods: 1988-2000,2001-2012.Death from heart disease was the primary end event,deaths from other causes were the competing events.Cumulative incidences of CSM was compared between groups.Competing risk model were used to assess the prognostic factors for CSM.Results: 5011 patients were included,46.1% of which received PORT.256 deaths of heart disease were observed.The cumulative incidences of CSM declined in period 2.Competing risk model adjusting sex,age,race,laterality,site,histology type,surgery type,PORT and year of diagnosis revealed that older age(?65)and squamous carcinoma increased risks of CSM.PORT did not reach statistically significant impact on CSM in all patients,but was associated with higher risk of CSM in subgroup analysis of patients with left lower lobe disease(SHR=2.382,95%CI:1.361-4.171,P = 0.002).Conclusions: Cumulative CSM incidences decreased in more recent years.PORT was associated with higher risk of CSM in patients with left lower lobe disease.Clinical attentiveness to cardiac-sparing radiotherapy should be paid and further studies are warranted.PART 3 PORT for NSCLC Patients with R1-resection at the Bronchial Stump: A Singleinstitutional Retrospective StudyPurpose: To investigate the proportion of R1-resection at the bronchial stump of radical NSCLC surgery in our hospital and explore the effect of PORT on those patients.Methods: We used SQL for data mining of our institutional database.We identified operations for malignancy in the lung through pathology reports and compared it with the data from Department of Statistics.Then we stepped forward to identify operations of primary non-metastatic NSCLC and operations with R1-resection at the bronchial stump.Results: We got 55434 cases of operations for malignancy in the lung from 2009,2010,2013-2019,with a 3.14% deviation compared with institutional statistics.The average proportion of R1-resections at the bronchial stump over all radical NSCLC surgeries was 2.28%,with declining trend over the years.In real world,the patterns of adjuvant therapy of patients differed a lot.PORT significantly improved OS in patients with positive lymph nodes,but seemed to have no influence on patients without lymph nodes involvement.Conclusions: It is feasible to dig institutional data with SQL.The proportion of R1-resections at the bronchial stump over all radical NSCLC surgeries is declining.Not all the R1-resection patients can benefit from PORT.A prospective observational cohort is warranted.