Extranodal extension in metastatic non-small cell lung cancer

Size and extranodal extension of metastatic lymph nodes in lung adenocarcinoma

Background

This study assessed the prognostic significance of metastatic lymph node size (MLNS) and extranodal extension (EN) in patients with node-positive lung adenocarcinoma (ADC).

Methods

Prognostic factors influencing survival were analyzed, including age, sex, extent of operation, T- and N-stage, size of tumor, postoperative chemotherapy, presence of EN, and MLNS (>7.0 vs. ≤7.0 mm).

Results

Three hundred seventy-five patients met the inclusion criteria were enrolled (mean age: 59.8±10.5 years). Increasing MLNS was significantly correlated with large tumor size (P=0.015), advanced N status (P<0.001), and presence of EN (P<0.001). In multivariable analysis, large tumor size [hazard ratio (HR) 1.135, 95% confidence interval (CI): 1.050 to 1.228, P<0.001], adjuvant chemotherapy (HR 0.582, 95% CI: 0.430 to 0.787, P<0.001), EN (HR 1.454, 95% CI: 1.029 to 2.055, P=0.034), and MLNS greater than 7 mm (HR 1.741, 95% CI: 1.238 to 2.447, P<0.001) were significant prognostic factors for survival. Patients were classified into 3 groups: Group A, MLNS ≤7.0 mm/EN (−); Group B, MLNS ≤7.0 mm/EN (+) or MLNS >7.0 mm/EN (−); and Group C, MLNS >7.0 mm/EN (+). The 5-year overall survival (OS) was 72.2%, 59.0%, and 38.5% in Groups A, B and C, respectively (P<0.001).

Conclusions

The MLNS and presence of EN could provide an important prognostic implication for patients with node-positive lung ADC.