New research was presented at AATS 2022, the American Association for Thoracic Surgery 102nd Annual Meeting, from May 14-27 in Boston. The features below highlight some of the studies emerging from the sessions.

STAS in Lung Adenocarcinoma Indicates Worse Outcome

For patients with lung adenocarcinoma, the presence of spread through air spaces (STAS) predicts a worse outcome, according to Andrea Wolf, MD, and colleagues. With the aim of defining potential factors associated with STAS that influence recurrence and survival, the study team examined patients (N=300) who underwent resection for T-3N0MN0 lung adenocarcinoma between January 2010 and June 2014 for the presence of STAS, STAS characteristics, farthest distance from tumor at which STAS was detected or maximal spread distance (MSD), and average density (number per slide). Of total lung adenocarcinoma cases, STAS was found in 56.7%. Median MSD was 2 mm, and 5-year overall survival (OS) in the STAS+ group was 75.9%, compared with 84.9% in STAS– group. Regression-free survival rates were 69.8% in the STAS+ group and 85.1% in the STAS– group. MSD and STAS density and characteristics were not linked with OS in a multi-variable Cox regression model. MSD appeared prognostic, however, with an estimated HR of 1.17 when adjusted by STAS characteristics and resection type. “Distance of lung adenocarcinoma STAS clusters from the main tumor may play a role in the worse OS and RFS seen in patients with STAS+ tumors,” the study authors wrote.

Lung Cancer Survival Similar Regardless of Smoking Status.

For patients with lung cancer who are light or never-smokers—defined via National Lung Screening Trial (NLST) and NELSON low-dose CT (LDCT) screening criteria—both overall 1-year and 5-year survival rates did not differ from those of heavy smokers. To determine whether such differences exist, Sandra L. Starnes, MD, and colleagues conducted SCREEN, a retrospective cohort study of patients with lung cancer, among whom 42.3% were heavy smokers, using NLST screening criteria. Among heavy smokers and light or never-smokers, median survival lengths were 6.9 and 7.1 years, respectively. Among heavy smokers and light or never smokers (HR, 1.05), both 1-year and 5-year Kaplan-Meier survival did not differ. Using the NELSON screening criteria, among heavy smokers and light or never-smokers, median survival lengths were 7.5 and 6.1 years, respectively. Between patients with lung cancer who were heavy smokers and light or never-smokers (HR, 0.90), Kaplan-Meier 1-year and 5-year survival did not differ. “These findings suggest that LDCT screening for the early detection of lung cancer should be studied in light or never-smokers,” the study authors wrote.

Better OS With Segmentectomy Vs Lobectomy for Some With NSCLC

Among patients with stage IA non-small cell lung cancer (NSCLC), segmentectomy was correlated with better survival than lobectomy in a subgroup who was younger, had fewer comorbidities, and was more likely to be treated at a high-volume facility, according to Varum Puri, MD, MSCI, and colleagues. Based on results of a Japanese trial that linked segmentectomy with better overall survival (OS) for stage IA NSCLC, the study team sought to determine whether similar results could be replicated in a United States cohort using a clinical registry representing 65% of US lung cancer cases diagnosed annually. Included in the investigation were patients with T1a-c N0 M0 NSCLC who underwent segmentectomy versus lobectomy during 2010-2018. The study team conducted a separate analysis among a subgroup of patients (N=6,685) similar to the patient cohort in the Japanese study (based on comorbidities, age, and tumor characteristics) to assess whether segmentectomy was linked with better OS than lobectomy. Of 93,549 patients diagnosed with stage IA NSCLC, 93.4% underwent lobectomy and 6.6% underwent segmentectomy. Segmentectomy was linked with worse OS when compared with lobectomy for stage IA NSCLC among all patients in the cohort, in multivariable (HR: 1.15) and propensity-score matched analyses (5-year survival, 67.8% vs 71.2%). However, segmentectomy was linked with better OS than lobectomy in the subgroup of patients who resembled the patient cohort in the Japanese study, in multivariable (HR: 0.57) and propensity score-matched analysis (5-year survival, 95.9% vs 91.2%).

Segmentectomy Rates Up for NSCLC

As segmentectomy has been recognized as a valid oncologic treatment option for patients with NSCLC, continued improvement is needed in the areas of tumor size selection and lymph node sampling, according to Bernard J. Park, MD, and colleagues. To investigate national trends in segmentectomy quality, the study team identified 406,882 patients with surgically treated NSCLC between 2004-2017. “Trends in successful adherence to 1) Commission on Cancer (CoC) guidelines of sampling 10 or more regional lymph nodes for pathological stage IA-IIB NSCLC, 2)n negative (R0) resection margins, and 3) tumor size ≤2cm were determined,” the study authors explained. They compared differences in odds of lymph node sampling adherence, appropriate tumor size selection, and negative margins, while controlling for clinical, socioeconomic, geographic, and hospital characteristics. Among participants, the proportion of segmentectomies increased from a mean of 2.9% per year from 2004-2007 to 4.6% per year from 2015-2017, compared with other types of lung resection. Community centers performed 54.8% of segmentectomies, while academic centers performed 45.2%. “Overall, successful adherence to 1) CoC lymph node sampling guidelines were met in 21.3% of patients who met pathological stage criteria, 2) an R0 resection was achieved in 93.4%, and 3) tumor size was ≤2cm in 55.1% of all cases,” the study authors noted, adding that improvement was observed with regard to adherence to all measures, from an average of 5.0% per year in 2004- 2007 to 18.2% per year in 2015-2017.

Worse NSCLC Outcomes at High Burden Hospitals

Treatment quality and outcomes in stage I and II NSCLC are correlated with hospital burden of uninsured and Medicaid-enrolled patents with NSCLC, according to Cherie P. Erkman, MD, and colleagues. “We hypothesized that a facility-level metric, defined as the percentage of uninsured or Medicaid-enrolled patients with NSCLC treated by a hospital, may influence treatment and outcomes in these patients,” Dr. Erkman explained. The study team sought to gain a better understanding of factors correlated with care at a hospital with a high proportion of uninsured or Medicaid-enrolled patients with NSCLC. Hospitals were categorized based of their relative burden of uninsured or
Medicaid-enrolled NSCLC patients into high burden (>13.2%), medium burden (7.7% – 13.2%), and low burden (<7.7%) tertiles. A total of 88,926 patients treated at 1,291 facilities were included in the study, with a percentage breakdown of 17.6% high burden hospitals (HBH), 22.0% medium burden hospitals (MBH), and 60.4% low burden hospitals (LBH). Patients at HBH were more likely to be male, younger, Black, or Hispanic, and more likely to reside in low-income, low-education, and rural regions. HBH were more likely to be academic and lower-volume facilities. Patients at HBH had a greater likelihood of having a length of stay greater than 4 days, not receiving surgery, unplanned readmission within 30 days of discharge, undergoing an open procedure, and undergoing a regional lymph node examination involving less than 10 lymph nodes, after controlling for confounders. In addition, patients treated at HBH were independently linked with an increased hazard of death (adjusted HR, 1.06). “Further efforts to understand the contribution of patient- versus facility-specific factors at high burden hospitals are required in order to improve outcomes in medically marginalized populations,” the study authors wrote.