Abstract 171P
Background
Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, and recurrence rates remain high even after complete resection of early-stage NSCLC. Lymph node micrometastasis, defined as tumor deposits between 0.2 mmand 2 mmin size, is not detected by routine pathology but may have prognostic implications. In this study, we examine the clinical significance of lymph node micrometastasis in NSCLC.
Methods
We conducted a retrospective observational study of 617 patients with pathologically confirmed T1-2aN0-1 NSCLC who underwent curative resection at Kanagawa Cardiovascular and Respiratory Disease Center from 2000 to 2015. Lymph node micrometastasis was assessed using immunohistochemistry (IHC) with cytokeratin staining in addition to digital slide analysis using the NanoZoomer® Virtual Slide System. The impact of micrometastasis on recurrence-free survival (RFS) and overall survival (OS) was analyzed using Kaplan-Meier and Cox proportional hazards models.
Results
Among the patients, 22 were identified with micrometastasis and 45 with macrometastasis. Patients with micrometastasis had significantly worse 5-year RFS (53.3% vs. 85.1%, p < 0.001) and OS (61.5% vs. 87.0%, p=0.007) compared to those without lymph node metastasis (N0). Cox regression analysis indicated that micrometastasis is an independent adverse prognostic factor for RFS (HR 2.545, p=0.009).
Conclusions
Lymph node micrometastasis significantly affects prognosis in NSCLC, with the hazard ratio for recurrence lying between N0 and macrometastasis. Further large-scale prospective studies are needed to validate these findings and improve treatment strategies for NSCLC.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.