Impact of Residual Mediastinal Nodal Disease After Neoadjuvant Chemoimmunotherapy for Non-Small Cell Lung Cancer.

Background/

Objectives

In recent years, neoadjuvant chemoimmunotherapy followed by surgery has improved outcomes in patients with stage II/III non-small cell lung cancer (NSCLC). However, the prognostic impact of residual mediastinal nodal disease after chemoimmunotherapy remains insufficiently defined, particularly with the introduction of the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) 9th edition nodal subclassification.

Methods

In this retrospective study, 90 consecutive patients with clinically node-positive (cN1-2) resectable locally advanced NSCLC who underwent neoadjuvant chemoimmunotherapy followed by curative-intent resection were included. Disease-free survival (DFS) was analyzed according to postoperative pathologic nodal status. Nodal status was assessed using the UICC/AJCC 8th edition (ypN0, ypN1, ypN2) and reclassified according to the 9th edition (ypN0, ypN1, ypN2a, ypN2b). Residual postoperative nodal disease was defined as residual pathologic nodal involvement (ypN+) in patients with clinically node-positive (cN+) disease at baseline.

Results

The cohort comprised 90 patients (60% male, median age 63 years [interquartile range (IQR) 58-69]). Following neoadjuvant therapy, surgery revealed pathologic nodal clearance in 53 (58.9%) and residual nodal disease in 37 (41.1%) patients (ypN1, n = 16 [17.8%]; ypN2a, n = 15 [16.7%]; and ypN2b, n = 6 [6.7%]). DFS differed significantly by postoperative nodal status (global log-rank p < 0.001), with progressively poorer outcomes with increasing residual nodal burden.

Conclusions

Residual nodal disease after neoadjuvant chemoimmunotherapy and surgery is associated with progressively inferior DFS according to its anatomic extent. The UICC/AJCC 9th-edition staging system provides clinically relevant prognostic granularity, supporting further investigation of mediastinal restaging and postoperative treatment strategies.