New research was presented at AATS 2019, The Annual Meeting of the American Association for Thoracic Surgery, from May 4-7 in Toronto. The features below highlight some of the studies presented at the conference.


Assessing Lung Adenocarcinoma With Spread Through Air Spaces

In 2015, spread through air spaces (STAS) in lung adenocarcinoma was a newly describe WHO classification. While previous studies indicate an association between STAS and clinicopathologic factors and suggest a prognostic impact on local recurrence, few have investigated the molecular features and immune landscapes of this phenomenon. Using the Cancer Genome Atlas, researchers analyzed the genetic profiles and clinical data of the whole-slide images of lung adenocarcinoma from patients with pathologic stage I disease in order to evaluate the correlation of STAS with somatically acquired DNA alterations, RNA transcripts, methylation loci, and immune landscapes, and to evaluate both overall and recurrence-free survival. Recurrence-free survival was 70% in STAS-negative patients and 62% in STAS-positive patients. Median overall survival was 42.8 for patients without STAS, compared with 22.3 months for those with STAS. In genomic analysis, the two groups had similar mutation load and heterogeneity. RNA sequencing data identified nine downregulated and 43 upregulated genes in STAS versus no STAS.


Pulmonary Resection After Neoadjuvant Immunotherapy

Early experience suggests that surgical resection after neoadjuvant immunotherapy (nIO) may pose unique challenges to those experienced after neo-adjuvant cytotoxic therapy in patients with early stage non-small cell lung cancer (NSCLC). For a study, researchers compared the surgical approach and perioperative outcomes of NSCLC patients receiving nIO with those of cohorts undergoing neoadjuvant chemotherapy (nCT). Complete minimally invasive resection was performed in 63% of nIO patients, compared with 42% of nCT patients, with less median blood loss (100cc vs. 150cc) and no statistical difference in operative time (172 min vs. 212 min.). Rate of conversion from minimally invasive to open were 12% in the nIO group and 235 in the nCT group. Complication and 30-day mortality (0%) rates were similar in both groups, as was median length of hospital stay.



Pulmonary Artery Sling Repair & Compete Tracheal Rings

Assessments of current practices and mid-term outcomes for patients with pulmonary artery sling (PAS) and complete tracheal rings (CTRs) with or without stenosis who have undergone vascular and tracheal repairs are lacking. To shed light in this area, researchers analyzed demographics, concurrent congenital heart disease, type of tracheal repair and additional interventions among patients who underwent surgical repair of PAS with or without tracheal reconstruction between 1996 and 2017 at their institution. Among patients in the study, 55% were male, median age at operation was 6.9 months, and 67% had CTR. Tracheal reconstruction was performed in 50%, most of which were performed at the time of PAS repair. Among those with initial tracheal repair, 60% require post-operative bronchoscopic interventions. Among those with CTR in the absence of tracheal stenosis, none required tracheal reconstruction. One-third of patients did not have CTR. Freedom from reintervention at a median follow-up of 6.4 years was 61%. The study authors concluded that airway reconstruction may be safely avoided in the absence of significant tracheal stenosis in patients with PAS and CTR.



Lung Cancer Screening With LDCT

Data indicate that rural populations are disproportionately impacted by tobacco use and lung cancer, with higher rates of late-stage diagnoses and mortality making them a key target for low dose CT (LDCT) screening. However, rural lung cancer screening experience is not well documented. To understand patient characteristics and lung cancer incidence in a rural lung cancer screening program to improve awareness and increase participation, study investigators evaluated data on patients of a rural, tertiary, academic institution who underwent LDCT from January 2014 to October 2018. In line with previous studies showing that rural patients are less likely to engage in an offer of screening or to undergo LDCT, the study team found a 58.5% follow-through rate among the study cohort. Yet, 94% of patients were diagnosed on their first LDCT, with 68% found to have early stage disease requiring surgery alone. “This, in combination with our higher prevalence at first screen compared to the [National Lung Cancer Screening Trial], provides compelling reasons to further investigate patient facilitators to participation in rural communities,” conclude the study authors, adding that “in order for lung cancer screening to become a more equitable early detection strategy, maintenance of high uptake among this population is vital.”



Sooner Vs Better-Quality Lung Transplant Donor

Evidence indicates that lung transplant donors are commonly refused by candidates hoping to receive a better-quality donor to provide improved outcomes. However, little is known regarding the effect of waiting for a low-risk donor compared to accepting a higher-risk donor offer sooner. For a study, the likelihood of 1-yearr mortality with varying donor risk, candidate risk, and time on waitlist were analyzed among double lung transplant patients and donors who were both classified into high-, medium-, and low-risk categories. At any risk level for the candidate, reducing waiting time was associated with a mortality advantage. Lower donor risk level also reduced mortality risk, but to a lesser extent, with mortality advantages varying with the combination of waiting time and donor risk. For low-risk recipients, waiting for a lower-risk donor (low- or medium-risk), even up to 6 months, offered a lower mortality than receiving a high-risk donor earlier. For medium-risk recipients, waiting for a lower-risk donor, up to 90 days, offered a lower mortality than receiving a high-risk donor earlier. For high-risk recipients, there was no survival benefit in waiting for a lower-risk donor beyond 7 days, for whom mortality ranged from 33% to 93% regardless of donor quality and was greater than 50% by 30 days. The study authors suggest that high-risk candidates “be transplanted as soon as any marginally acceptable donor is available.”