Lymphatic Invasion Acts as a 'Hidden Risk Factor': Four-Fold Increased Mortality Risk in Early-Stage (TNM Stage I,...

Area of Science:

• Oncology
• Surgical Pathology
• Cancer Prognostics

Background:

• Early-stage non-small cell lung cancer (NSCLC) exhibits prognostic heterogeneity despite TNM staging.
• Lymphatic invasion (LI) is recognized as an aggressive marker, but its impact in low-risk Stage I NSCLC is unclear.

Purpose of the Study:

• To investigate the independent prognostic significance of lymphatic invasion (LI) in early-stage non-small cell lung cancer (NSCLC).
• To evaluate the role of LI in a subgroup of low-risk Stage I, N0 NSCLC patients.

Main Methods:

• Retrospective cohort study of 988 patients undergoing curative resection for NSCLC.
• Analysis included TNM staging (9th Edition) and grouping by lymphatic invasion (LI) status.
• Overall survival (OS) assessed using Kaplan-Meier and multivariable Cox models, with a focus on a low-risk subgroup (n=347).

Main Results:

• Lymphatic invasion (LI) was present in 40.9% of the cohort and independently predicted worse overall survival (OS) (HR: 1.520, p=0.048).
• In the low-risk subgroup, 5-year OS declined from 96.1% (LI-negative) to 83.8% (LI-positive).
• LI was confirmed as an independent adverse prognostic factor in the low-risk subgroup (HR: 4.002, p=0.004).

Conclusions:

• Lymphatic invasion (LI) is a robust, independent adverse prognostic factor in resected NSCLC.
• LI may identify early-stage N0 NSCLC patients needing closer surveillance or adjuvant therapy consideration.
• Prospective validation is needed for integrating LI into staging or treatment guidelines.