Lymph node assessment should be expanded in patients undergoing surgery for non-small-cell lung cancer (NSCLC) to more accurately detect hidden systemic disease, suggests research presented at the 2026 Society of Thoracic Surgeons Annual Meeting.
The study “represents the largest analysis to date examining the real-world outcomes of patients with varying extents of lymph node dissection,” said study author Christopher Seder, MD, a thoracic surgeon at Rush University Medical Center in Chicago.
“Our findings suggest that in clinical node-negative NSCLC, assessment of more than one N1 nodal station, including station 12-14 lymph nodes, is associated with increased nodal upstaging and improved stage stratification,” he told Inside Precision Medicine.
Seder explained that most studies and guidelines have focused on mediastinal N2 nodes—lymph nodes found in the center of the chest that drain lymph from the lungs. His team wanted to shift the focus to N1 nodes, i.e., those that are within or immediately adjacent to the lungs, because increasing data is showing that any nodal spread is associated with systemic disease.
At present, North American surgical standards call for assessment of three N2 nodes in the mediastinum between the right and left lungs, and one N1 node in the root of the lung of patients with clinically node-negative NSCLC (cancer that diagnostic imaging shows has not spread) but recommendations vary globally.
To investigate how the extent of nodal assessment can impact disease upstaging, Seder and colleagues reviewed data for 48,779 patients with clinically node-negative NSCLC who underwent lobectomy (64.4%), wedge resection (18.5%), or segmentectomy (17.1%) between 2021 and 2024 across 279 centers that reported to the Society of Thoracic Surgeons General Thoracic Surgery Database. Patients who had received neoadjuvant therapy were excluded from the study.
Seder reported that, after surgery, 11.2% of patients had pathologic nodal upstaging, meaning that their cancers were more advanced than originally thought.
Furthermore, the rate of increase in nodal upstaging rate was greater with each additional N1 station assessed than with each additional N2 station assessed, with no effect on major perioperative morbidity.
Importantly, nearly one in five patients (19.7%) were upstaged due to malignancy exclusively identified in N1 intrapulmonary lymph nodes (stations 12-14), which Seder said “shows the importance of evaluating these N1 stations when doing any lung cancer operation.”
For patients with longitudinal data (n=22,644), the researchers found that the 3-year overall survival rate increased significantly with each additional N1 lymph node station sampled.
After adjustment for age, sex, tumor characteristics, and type of surgery, assessment of more N1 stations remained associated with improved overall survival and this improved survival was more pronounced when intrapulmonary (stations 12-14) were evaluated.
“Nearly all patients who undergo anatomic resection have station 12-14 lymph nodes removed at surgery,” said Seder. “The key is identifying them and having pathology report them out.”
“So, this is really a call-to-action for both the surgeon, to dissect out and label more individual N1 nodes—regardless of the operation being performed—and the pathologist to compete a more thorough specimen examination,” he added.
Seder also reported that the findings remained consistent in the sub-cohort of 30,369 patients with clinically node-negative NSCLC tumors that were 2 cm or smaller.
He believes that the findings “could have direct implications for surgical, pathologic, and oncologic guidelines,” but whether recommendations will change is still unclear.
“It’s one more piece of the puzzle,” he said, adding that there are practical reasons why it may not always be possible for surgeons to obtain lymph nodes from more than one N1 station. “Although our results were consistent in tumors ≤2 cm, small peripheral wedge resections may not yield multiple intraparenchymal lymph nodes or there may not be nodal tissue available at certain stations. So, setting the compliance bar at two or three N1 stations could result in penalizing surgeons for resections that are otherwise appropriate, especially in patients with ground glass opacities or low-risk, small, peripheral lesions.”
“Our hope is that these data and the balanced discussion in our manuscript will be considered by multidisciplinary consensus groups when revising future guidelines and standards.”
Seder believes that the take home message from the study is that “N1 nodes might matter more than we gave them credit for,” but he stresses that the research “should not be interpreted as suggesting that anatomic resection is indicated for the purpose of facilitating more extensive N1 nodal evaluation.”
