Necroptosis triggers spatially restricted neutrophil-mediated vascular damage during lung ischemia reperfusion injury.

Ischemia reperfusion injury represents a common pathological condition that is triggered by the release of endogenous ligands. While neutrophils are known to play a critical role in its pathogenesis, the tissue-specific spatiotemporal regulation of ischemia-reperfusion injury is not understood. Here, using oxidative lipidomics and intravital imaging of transplanted mouse lungs that are subjected to severe ischemia reperfusion injury, we discovered that necroptosis, a nonapoptotic form of cell death, triggers the recruitment of neutrophils. During the initial stages of inflammation, neutrophils traffic predominantly to subpleural vessels, where their aggregation is directed by chemoattractants produced by nonclassical monocytes that are spatially restricted in this vascular compartment. Subsequent neutrophilic disruption of capillaries resulting in vascular leakage is associated with impaired graft function. We found that TLR4 signaling in vascular endothelial cells and downstream NADPH oxidase 4 expression mediate the arrest of neutrophils, a step upstream of their extravasation. Neutrophil extracellular traps formed in injured lungs and their disruption with DNase prevented vascular leakage and ameliorated primary graft dysfunction. Thus, we have uncovered mechanisms that regulate the initial recruitment of neutrophils to injured lungs, which result in selective damage to subpleural pulmonary vessels and primary graft dysfunction. Our findings could lead to the development of new therapeutics that protect lungs from ischemia reperfusion injury.

Smoking exposure-induced bronchus-associated lymphoid tissue in donor lungs does not prevent tolerance induction after transplantation.

The presence of bronchus-associated lymphoid tissue (BALT) in donor lungs has been suggested to accelerate graft rejection after lung transplantation. Although chronic smoke exposure can induce BALT formation, the impact of donor cigarette use on alloimmune responses after lung transplantation is not well understood. Here, we show that smoking-induced BALT in mouse donor lungs contains Foxp3+ T cells and undergoes dynamic restructuring after transplantation, including recruitment of recipient-derived leukocytes to areas of pre-existing lymphoid follicles and replacement of graft-resident donor cells. Our findings from mouse and human lung transplant data support the notion that a donor's smoking history does not predispose to acute cellular rejection or prevent the establishment of allograft acceptance with comparable outcomes to nonsmoking donors. Thus, our work indicates that BALT in donor lungs is plastic in nature and may have important implications for modulating proinflammatory or tolerogenic immune responses following transplantation.

Validation of a novel donor lung scoring system based on the updated lung Composite Allocation Score.

Lung transplantation (LTx) continues to have lower rates of long-term graft survival compared with other organs. Additionally, lung utilization rates from brain-dead donors remain substantially lower compared with other solid organs, despite a growing need for LTx and the significant risk of waitlist mortality. This study aims to examine the effects of using a combination of the recently described novel lung donor (LUNDON) acceptability score and the newly adopted recipient lung Composite Allocation Score (CAS) to guide transplantation. We performed a review of nearly 18 000 adult primary lung transplants from 2015-2022 across the US with retroactive calculations of the CAS value. The medium-CAS group (29.6-34.5) had superior 1-year posttransplant survival. Importantly, the combination of high-CAS (> 34.5) recipients with low LUNDON score (≤ 40) donors had the worst survival at 1 year compared with any other combination. Additionally, we constructed a model that predicts 1-year and 3-year survival using the LUNDON acceptability score and CAS values. These results suggest that caution should be exercised when using marginally acceptable donor lungs in high-priority recipients. The use of the LUNDON score with CAS value can potentially guide clinical decision-making for optimal donor-recipient matches for LTx.

Development and validation of the lung donor (LUNDON) acceptability score for pulmonary transplantation.

There is a chronic shortage of donor lungs for pulmonary transplantation due, in part, to low lung utilization rates in the United States. We performed a retrospective cohort study using data from the Scientific Registry of Transplant Recipients database (2006-2019) and developed the lung donor (LUNDON) acceptability score. A total of 83 219 brain-dead donors were included and were randomly divided into derivation (n = 58 314, 70%) and validation (n = 24 905, 30%) cohorts. The overall lung acceptance was 27.3% (n = 22 767). Donor factors associated with the lung acceptance were age, maximum creatinine, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen, mechanism of death by asphyxiation or drowning, history of cigarette use (≥20 pack-years), history of myocardial infarction, chest x-ray appearance, bloodstream infection, and the occurrence of cardiac arrest after brain death. The prediction model had high discriminatory power (C statistic, 0.891; 95% confidence interval, 0.886-0.895) in the validation cohort. We developed a web-based, user-friendly tool (available at https://sites.wustl.edu/lundon) that provides the predicted probability of donor lung acceptance. LUNDON score was also associated with recipient survival in patients with high lung allocation scores. In conclusion, the multivariable LUNDON score uses readily available donor characteristics to reliably predict lung acceptability. Widespread adoption of this model may standardize lung donor evaluation and improve lung utilization rates.

Assessment of Duration of Smoking Cessation Prior to Surgical Treatment of Non-small Cell Lung Cancer.

OBJECTIVE: To define the relationship between the duration of smoking cessation and postoperative complications for patients with lung cancer undergoing surgical treatment. BACKGROUND: Smoking increases the risk of postoperative morbidity and mortality in patients with lung cancer undergoing surgical treatment. Although smoking cessation before surgery can mitigate these risks, the ideal duration of preoperative smoking cessation remains unclear. METHODS: Using a uniquely compiled Veterans Health Administration dataset, we performed a retrospective cohort study of patients with clinical stage I non-small cell lung cancer undergoing surgical treatment between 2006 and 2016. We characterized the relationship between duration of preoperative smoking cessation and risk of postoperative complications or mortality within 30-days using multivariable restricted cubic spline functions. RESULTS: The study included a total of 9509 patients, of whom 6168 (64.9%) were smoking at the time of lung cancer diagnosis. Among them, only 662 (10.7%) patients stopped smoking prior to surgery. Longer duration between smoking cessation and surgery was associated with lower odds of major complication or mortality (adjusted odds ratio [aOR] for every additional week, 0.919; 95% confidence interval [CI], 0.850-0.993; P = 0.03). Compared to nonsmokers, patients who quit at least 3 weeks before surgery had similar odds of death or major complication (aOR, 1.005; 95% CI, 0.702-1.437; P = 0.98) whereas those who quit within 3 weeks of surgery had significantly higher odds of death or major complication (aOR, 1.698; 95% CI, 1.203-2.396; P = 0.003). CONCLUSION: Smoking cessation at least 3 weeks prior to the surgical treatment of lung cancer is associated with reduced morbidity and mortality. Providers should aggressively encourage smoking cessation in the preoperative period, since it can disproportionately impact outcomes in early-stage lung cancer.

Comparison Between Veteran and Non-Veteran Populations With Clinical Stage I Non-small Cell Lung Cancer Undergoing Surgery.

OBJECTIVE: The aim of this study was to compare quality of care and outcomes between Veteran and non-Veteran patients undergoing surgery for clinical stage I non-small cell lung cancer (NSCLC). BACKGROUND: Prior studies and the lay media have questioned the quality of care that Veterans with lung cancer receive through the VHA. We hypothesized Veterans undergoing surgery for early-stage NSCLC receive high quality care and have similar outcomes compared to the general population. METHODS: We performed a retrospective cohort study of patients with clinical stage I NSCLC undergoing resection from 2006 to 2016 using a VHA dataset. Propensity score matching for baseline patient- and tumor-related variables was used to compare operative characteristics and outcomes between the VHA and the National Cancer Database (NCDB). RESULTS: The unmatched cohorts included 9981 VHA and 176,304 NCDB patients. The VHA had more male, non-White patients with lower education levels, higher incomes, and higher Charlson/Deyo scores. VHA patients had inferior unadjusted 30-day mortality (VHA 2.1% vs NCDB 1.7%, P = 0.011) and median overall survival (69.0 vs 88.7 months, P < 0.001). In the propensity matched cohort of 6792 pairs, VHA patients were more likely to have minimally invasive operations (60.0% vs 39.6%, P < 0.001) and only slightly less likely to receive lobectomies (70.1% vs 70.7%, P = 0.023). VHA patients had longer lengths of stay (8.1 vs 7.1 days, P < 0.001) but similar readmission rates (7.7% vs 7.0%, P = 0.132). VHA patients had significantly better 30-day mortality (1.9% vs 2.8%, P < 0.001) and median overall survival (71.4 vs 65.2 months, P < 0.001). CONCLUSIONS: Despite having more comorbidities, Veterans receive exceptional care through the VHA with favorable outcomes, including significantly longer overall survival, compared to the general population.

Development and Validation of the VA Lung Cancer Mortality (VALCAN-M) Score for 90-Day Mortality Following Surgical Treatment of Clinical Stage I Lung Cancer.

OBJECTIVE: The aim was to develop and validate the Veterans Administration (VA) Lung Cancer Mortality (VALCAN-M) score, a risk prediction model for 90-day mortality following surgical treatment of clinical stage I nonsmall-cell lung cancer (NSCLC). BACKGROUND: While surgery remains the preferred treatment for functionally fit patients with early-stage NSCLC, less invasive, nonsurgical treatments have emerged for high-risk patients. Accurate risk prediction models for postoperative mortality may aid surgeons and other providers in optimizing patient-centered treatment plans. METHODS: We performed a retrospective cohort study using a uniquely compiled VA data set including all Veterans with clinical stage I NSCLC undergoing surgical treatment between 2006 and 2016. Patients were randomly split into derivation and validation cohorts. We derived the VALCAN-M score based on multivariable logistic regression modeling of patient and treatment variables and 90-day mortality. RESULTS: A total of 9749 patients were included (derivation cohort: n=6825, 70.0%; validation cohort: n=2924, 30.0%). The 90-day mortality rate was 4.0% (n=390). The final multivariable model included 11 factors that were associated with 90-day mortality: age, body mass index, history of heart failure, forced expiratory volume (% predicted), history of peripheral vascular disease, functional status, delayed surgery, American Society of Anesthesiology performance status, tumor histology, extent of resection (lobectomy, wedge, segmentectomy, or pneumonectomy), and surgical approach (minimally invasive or open). The c statistic was 0.739 (95% CI=0.708-0.771) in the derivation cohort. CONCLUSIONS: The VALCAN-M score uses readily available treatment-related variables to reliably predict 90-day operative mortality. This score can aid surgeons and other providers in objectively discussing operative risk among high-risk patients with clinical stage I NSCLC considering surgery versus other definitive therapies.

Donor extracellular vesicle trafficking via the pleural space represents a novel pathway for allorecognition after lung transplantation.

Restoration of lymphatic drainage across the bronchial anastomosis after lung transplantation requires several weeks. As donor antigen and antigen presenting cell trafficking via lymphatics into graft-draining lymph nodes is an important component of the alloresponse, alternative pathways must exist that account for rapid rejection after pulmonary transplantation. Here, we describe a novel allorecognition pathway mediated through donor extracellular vesicle (EV) trafficking to mediastinal lymph nodes via the pleural space. Pleural fluid collected early after lung transplantation in rats and humans contains donor-specific EVs. In a fully MHC mismatched rat model of lung transplantation, we demonstrate EVs carrying donor antigen preferentially accumulate in mediastinal lymph nodes and colocalize with MHC II expressing cells within 4 h of engraftment. Injection of allogeneic EVs into pleural space of syngeneic lung transplant recipients confirmed their selective trafficking to mediastinal lymph nodes and resulted in activation of T cells in mediastinal, but not peripheral lymph nodes. Thus, we have uncovered an alternative pathway of donor antigen trafficking where pulmonary EVs released into the pleural space traffic to locoregional lymph nodes via pleural lymphatics. This pathway obviates the need for restoration of lymphatics across the bronchial anastomosis for trafficking of donor antigen to draining lymph nodes.

Different-team procurements: A potential solution for the unintended consequences of change in lung allocation policy.

The new lung allocation policy has led to an increase in distant donors and consequently enhanced logistical burden of procuring organs. Though early single-center studies noted similar outcomes between same-team transplantation (ST, procuring team from transplanting center) and different-team transplantation (DT, procuring team from different center), the efficacy of DT in the contemporary era remains unclear. In this study, we evaluated the trend of DT, rate of transplanting both donor lungs, 1-year graft survival, and risk of Grade 3 primary graft dysfunction (PGD) using the Scientific Registry of Transplant Recipient (SRTR) database from 2006 to 2018. A total of 21619 patients (DT 2085, 9.7%) with 19837 donors were included. Utilization of DT decreased from 15.9% in 2006 to 8.5% in 2018. Proportions of two-lung donors were similar between the groups, and DT had similar 1-year graft survival as ST for both double (DT, HR 1.108, 95% CI 0.894-1.374) and single lung transplants (DT, HR 1.094, 95% CI 0.931-1.286). Risk of Grade 3 PGD was also similar between ST and DT. Given our results, expanding DT may be a feasible option for improving lung procurement efficiency in the current era, particularly in light of the COVID-19 pandemic.

Bacterial products in donor airways prevent the induction of lung transplant tolerance.

Although postoperative bacterial infections can trigger rejection of pulmonary allografts, the impact of bacterial colonization of donor grafts on alloimmune responses to transplanted lungs remains unknown. Here, we tested the hypothesis that bacterial products present within donor grafts at the time of implantation promote lung allograft rejection. Administration of the toll-like receptor 2 (TLR2) agonist Pam3 Cys4 to Balb/c wild-type grafts triggered acute cellular rejection after transplantation into B6 wild-type recipients that received perioperative costimulatory blockade. Pam3 Cys4 -triggered rejection was associated with an expansion of CD8+ T lymphocytes and CD11c+ CD11bhi MHC (major histocompatibility complex) class II+ antigen-presenting cells within the transplanted lungs. Rejection was prevented when lungs were transplanted into TLR2-deficient recipients but not when MyD88-deficient donors were used. Adoptive transfer of B6 wild-type monocytes, but not T cells, following transplantation into B6 TLR2-deficient recipients restored the ability of Pam3 Cys4 to trigger acute cellular rejection. Thus, we have demonstrated that activation of TLR2 by a bacterial lipopeptide within the donor airways prevents the induction of lung allograft tolerance through a process mediated by recipient-derived monocytes. Our work suggests that donor lungs harboring bacteria may precipitate an inflammatory response that can facilitate allograft rejection.

Donor management using a specialized donor care facility is associated with higher organ utilization from drug overdose donors.

Drug overdoses have tripled in the United States over the last two decades. With the increasing demand for donor organs, one potential consequence of the opioid epidemic may be an increase in suitable donor organs. Unfortunately, organs from donors dying of drug overdose have poorer utilization rates than other groups of brain-dead donors, largely due to physician and recipient concerns about viral disease transmission. During the study period of 2011 to 2016, drug overdose donors (DODs) account for an increasingly greater proportion of the national donor pool. We show that a novel model of donor care, known as specialized donor care facility (SDCF), is associated with an increase in organ utilization from DODs compared to the conventional model of hospital-based donor care. This is likely related to the close relationship of the SDCF with the transplant centers, leading to improved communication and highly efficient donor care.

Microbiota in heart and lung transplantation: implications for innate-adaptive immune interface.

PURPOSE OF REVIEW: Transplantation continues to be the only treatment option for end-stage organ failure when other interventions have failed. Although short-term outcomes have improved due to advances in perioperative care, long-term outcomes continue to be adversely affected by chronic rejection. Little is known about the role microbiota play in modulating alloimmune responses and potentially contributing to graft failure. Initial data have identified a correlation between specific changes of the recipient and/or donor microbiota and transplant outcomes. In this review, we will focus on recent findings concerning the complex interplay between microbiota and the innate immune system after heart and lung transplantation. RECENT FINDINGS: Gut microbiome derangements in heart failure promote an inflammatory state and have lasting effects on the innate immune system, with an observed association between increased levels of microbiota-dependent metabolites and acute rejection after cardiac transplantation. The lung allograft microbiome interacts with components of the innate immune system, such as toll-like receptor signalling pathways, NKG2C+ natural killer cells and the NLRP3 inflammasome, to alter posttransplant outcomes, which may result in the development of chronic rejection. SUMMARY: The innate immune system is influenced by alterations in the microbiome before and after heart and lung transplantation, thereby offering potential therapeutic targets for prolonging allograft survival.

Comparison of outcomes in lung and heart transplant recipients from the same multiorgan donor.

BACKGROUND: Primary graft dysfunction (PGD) and acute cellular rejection (ACR) are important causes of early morbidity and mortality following lung and heart transplantation. While many studies have elucidated donor-related risk factors of PGD and ACR, these complications often occur even with "ideal" donors. Therefore, we investigated potential associations of PGD and ACR between bilateral lung and heart transplant recipients from the same multiorgan donor, respectively. METHODS: Between 2011 and 2017, 100 donors contributed 100 bilateral lung transplants and 100 heart transplants performed. Logistic regression analysis for PGD and Cox proportional hazards regression analysis for ACR were used to estimate the relationship of heart and lung transplants. RESULTS: The incidence of PGD was 33% among lung and 17% among heart transplant recipients. Similarly, the incidence of ACR grade ≥ A2 for lung recipients was 38% (30/80), and the incidence of ACR grade ≥ 2R for heart recipients was 19% (15/80). There was no association between the development of PGD and ACR in lung and heart transplant recipients from the same donor, respectively. CONCLUSIONS: These findings suggest that inherent donor factors are not critical to the development of PGD and ACR after lung and heart transplantation.

Unintended consequences of changes to lung allocation policy.

Organ allocation for transplantation aims to balance the principles of justice and medical utility to optimally utilize a scarce resource. To address practical considerations, the United States is divided into 58 donor service areas (DSA), each constituting the first unit of allocation. In November 2017, in response to a lawsuit in New York, an emergency action change to lung allocation policy replaced the DSA level of allocation for donor lungs with a 250 nautical mile circle around the donor hospital. Similar policy changes are being implemented for other organs including heart and liver. Findings from a recent US Department of Health and Human Services report, supplemented with data from our institution, suggest that the emergency policy has not resulted in a change in the type of patients undergoing lung transplantation (LT) or early postoperative outcomes. However, there has been a significant decline in local LT, where donor and recipient are in the same DSA. With procurement teams having to travel greater distances, organ ischemic time has increased and median organ cost has more than doubled. We propose potential solutions for consideration at this critical juncture in the field of transplantation. Policymakers should choose equitable and sustainable access for this lifesaving discipline.

Cutting edge: Pseudomonas aeruginosa abolishes established lung transplant tolerance by stimulating B7 expression on neutrophils.

The mechanisms that link bacterial infection to solid organ rejection remain unclear. In this study, we show that following the establishment of lung allograft acceptance in mice, Pseudomonas aeruginosa airway infection induces a G-CSF-dependent neutrophilia that stimulates acute rejection. Graft-infiltrating neutrophils sharply upregulate the B7 molecules CD80 and CD86, but they do not express CD40 or MHC class II in response to P. aeruginosa infection. Neutrophil B7 promotes naive CD4(+) T cell activation and intragraft IL-2(+), IFN-γ(+), and IL-17(+) T lymphocyte accumulation. Intravital two-photon microscopy reveals direct interactions between neutrophils and CD4(+) T cells within pulmonary allografts. Importantly, lung rejection in P. aeruginosa-infected recipients is triggered by CD80/86 on neutrophils and can be prevented by B7 blockade without affecting clearance of this pathogen. These data show that neutrophils enhance T cell activation through B7 trans-costimulation and suggest that inhibiting neutrophil-mediated alloimmunity can be accomplished without compromising bacterial immune surveillance.

Murine Left Pulmonary Hilar Clamp Model of Lung Ischemia Reperfusion Injury.

Ischemia reperfusion injury (IRI) during lung transplantation is a major risk factor for post-transplant complications, including primary graft dysfunction, acute and chronic rejection, and mortality. Efforts to study the underpinnings of IRI led to the development of a reliable and reproducible mouse model of left lung hilar clamping. This model involves a surgical procedure performed in an anesthetized and intubated mouse. A left thoracotomy is performed, followed by careful lung mobilization and dissection of the left pulmonary hilum. The hilar clamp involves reversible suture ligation of the pulmonary hilum with a slipknot, which stops the arterial inflow, venous outflow, and airflow through the left mainstem bronchus. Reperfusion is initiated by careful removal of the suture. Our laboratory uses 30 min of ischemia and 1 h of reperfusion for the experimental model in the current investigations. However, these time periods can be modified depending on the specific experimental question. Immediately prior to sacrifice, arterial blood gas can be obtained from the left ventricle after a 4 min period of right hilar clamping to ensure that the PaO2 values obtained are attributed to the injured left lung alone. We also describe a method to measure cell extravasation with flow cytometry, which involves intravenous injection of a fluorochrome-labeled antibody specific for the cell(s) to be studied prior to sacrifice. The left lung can then be harvested for flow cytometry, frozen or fixed, paraffin-embedded immunohistochemistry, and quantitative polymerase chain reaction. This hilar clamp technique allows for detailed study of the cellular and molecular mechanisms underlying IRI. Representative results reveal decreased left lung oxygenation and histologic evidence of lung injury following hilar clamping. This technique can be readily learned and reproduced by personnel with and without microsurgical experience, leading to reliable and consistent results and serving as a widely adoptable model for studying lung IRI.

Intravital Two-Photon Microscopy of the Transplanted Mouse Lung.

Complications after lung transplantation are largely related to the host immune system responding to the graft. Such immune responses are regulated by crosstalk between donor and recipient cells. A better understanding of these processes relies on the use of preclinical animal models and is aided by an ability to study intra-graft immune cell trafficking in real-time. Intravital two-photon microscopy can be used to image tissues and organs for depths up to several hundred microns with minimal photodamage, which affords a great advantage over single-photon confocal microscopy. Selective use of transgenic mice with promoter-specific fluorescent protein expression and/or adoptive transfer of fluorescent dye-labeled cells during intravital two-photon microscopy allows for the dynamic study of single cells within their physiologic environment. Our group has developed a technique to stabilize mouse lungs, which has enabled us to image cellular dynamics in naïve lungs and orthotopically transplanted pulmonary grafts. This technique allows for detailed assessment of cellular behavior within the vasculature and in the interstitium, as well as for examination of interactions between various cell populations. This procedure can be readily learned and adapted to study immune mechanisms that regulate inflammatory and tolerogenic responses after lung transplantation. It can also be expanded to the study of other pathogenic pulmonary conditions.

Exposure to Agent Orange is associated with increased recurrence after surgical treatment of stage I non-small cell lung cancer.

OBJECTIVE: Approximately 3 million Americans served in the armed forces during the Vietnam War. Veterans have a higher incidence rate of lung cancer compared with the general population, which may be related to exposures sustained during service. Agent Orange, one of the tactical herbicides used by the armed forces as a means of destroying crops and clearing vegetation, has been linked to the development of several cancers including non-small cell lung cancer. However, traditional risk models of lung cancer survival and recurrence often do not include such exposures. We aimed to examine the relationship between Agent Orange exposure and overall survival and disease recurrence for surgically treated stage I non-small cell lung cancer. METHODS: We performed a retrospective cohort study using a uniquely compiled dataset of US Veterans with pathologic I non-small cell lung cancer. We included adult patients who served in the Vietnam War and underwent surgical resection between 2010 and 2016. Our 2 comparison groups included those with identified Agent Orange exposure and those who were unexposed. We used multivariable Cox proportional hazards and Fine and Gray competing risk analyses to examine overall survival and disease recurrence for patients with pathologic stage I disease, respectively. RESULTS: A total of 3958 Vietnam Veterans with pathologic stage I disease were identified (994 who had Agent Orange exposure and 2964 who were unexposed). Those who had Agent Orange exposure were more likely to be male, to be White, and to live a further distance from their treatment facility (P < .05). Tumor size distribution, grade, and histology were similar between cohorts. Multivariable Cox proportional hazards modeling identified similar overall survival between cohorts (Agent Orange exposure hazard ratio, 0.97; 95% CI, 0.86-1.09). Patients who had Agent Orange exposure had a 19% increased risk of disease recurrence (hazard ratio, 1.19; 95% CI, 1.02-1.40). CONCLUSIONS: Veterans with known Agent Orange exposure who undergo surgical treatment for stage I non-small cell lung cancer have an approximately 20% increased risk of disease recurrence compared with their nonexposed counterparts. Agent Orange exposure should be taken into consideration when determining treatment and surveillance regimens for Veteran patients.

Factors associated with incomplete resection for large, locally invasive non-small cell lung cancer.

Background: Large, node-negative but locally invasive non-small cell lung cancer (NSCLC) is associated with increased perioperative risk but improved survival if a complete resection is obtained. Factors associated with positive margins in this population are not well-studied. Methods: We performed a retrospective cohort study using National Cancer Database (NCDB) for adult patients with >5 cm, clinically node-negative NSCLC with evidence of invasion of nearby structures [2006-2015]. Patients were classified as having major structure involvement (azygous vein, pulmonary artery/vein, vena cava, carina/trachea, esophagus, recurrent laryngeal/vagus nerve, heart, aorta, vertebrae) or chest wall invasion (rib pleura, chest wall, diaphragm). Our primary outcome was to evaluate factors associated with incomplete resection (microscopic: R1, macroscopic: R2). Kaplan-Meier analysis and cox multivariable regression models were used to evaluate overall survival (OS), 90-day mortality, and factors associated with positive margins. Results: Among 2,368 patients identified, the median follow-up was 33.8 months [interquartile range (IQR), 12.6-66.5 months]. Most patients were white (86.9%) with squamous cell histology (47.3%). Major structures were involved in 26.4% of patients and chest wall invasion was seen in 73.6%. Four hundred and seventy-eight patients (20.2%) had an incomplete resection. Multivariable analysis revealed that black race [hazard ratio (HR) 1.568, 95% confidence interval (CI): 1.109-2.218] and major structure involvement (HR 1.412, 95% CI: 1.091-1.827) was associated with increased risk of incomplete resection and surgery at an academic hospitals (HR 0.773, 95% CI: 0.607-0.984), adenocarcinoma histology (HR 0.672, 95% CI: 0.514-0.878), and neoadjuvant chemotherapy (HR 0.431, 95% CI: 0.316-0.587) were associated with decreased risk of incomplete resection. The 5-year OS was 43.7% in the entire cohort and 28.8% in patients with positive margins and 47.5% in patients with an R0 resection. Positive margin was also associated with a significantly higher 90-day mortality rate (9.9% versus 6.7%). Conclusions: For patients with large, node-negative NSCLC invading nearby structures, R0 resection portends better survival. Treatment at academic centers, adenocarcinoma histology, and receipt of neoadjuvant chemotherapy are associated with R0 resection in this high-risk cohort.

Lobe-specific lymph node sampling is associated with lower risk of cancer recurrence.

Objective: Adequate intraoperative lymph node (LN) assessment is a critical component of early-stage non-small cell lung cancer (NSCLC) resection. The National Comprehensive Cancer Network and the American College of Surgeons Commission on Cancer (CoC) recommend station-based sampling minimums agnostic to tumor location. Other institutions advocate for lobe-specific LN sampling strategies that consider the anatomic likelihood of LN metastases. We examined the relationship between lobe-specific LN assessment and long-term outcomes using a robust, highly curated cohort of stage I NSCLC patients. Methods: We performed a cohort study using a uniquely compiled dataset from the Veterans Health Administration and manually abstracted data from operative and pathology reports for patients with clinical stage I NSCLC (2006-2016). For simplicity in comparison, we included patients who had right upper lobe (RUL) or left upper lobe (LUL) tumors. Based on modified European Society of Thoracic Surgeons guidelines, lobe-specific sampling was defined for RUL tumors (stations 2, 4, 7, and 10 or 11) and LUL tumors (stations 5 or 6, 7, and 10 or 11). Our primary outcome was the risk of cancer recurrence, as assessed by Fine and Gray competing risks modeling. Secondary outcomes included overall survival (OS) and pathologic upstaging. Analyses were adjusted for relevant patient, disease, and treatment variables. Results: Our study included 3534 patients with RUL tumors and 2667 patients with LUL tumors. Of these, 277 patients (7.8%) with RUL tumors and 621 patients (23.2%) with LUL tumors met lobe-specific assessment criteria. Comparatively, 34.7% of patients met the criteria for count-based assessment, and 25.8% met the criteria for station-based sampling (ie, any 3 N2 stations and 1 N1 station). Adherence to lobe-specific assessment was associated with lower cumulative incidence of recurrence (adjusted hazard ratio [aHR], 0.83; 95% confidence interval [CI], 0.70-0.98) and a higher likelihood of pathologic upstaging (aHR, 1.49; 95% CI, 1.20-1.86). Lobe-specific assessment was not associated with OS. Conclusions: Adherence to intraoperative LN sampling guidelines is low. Lobe-specific assessment is associated with superior outcomes in early-stage NSCLC. Quality metrics that assess adherence to intraoperative LN sampling, such as the CoC Operative Standards manual, also should consider lobe-specific criteria.