Number of metastatic lymph nodes and zones as prognostic factors in non-small-cell lung cancer

Interact Cardiovasc Thorac Surg. 2020 Sep 1;31(3):305-314. doi: 10.1093/icvts/ivaa107.

Abstract

Objectives: Characterizing pathological nodes (pNs) by location alone is sometimes inadequate as patients with pN1 or pN2 non-small-cell lung cancer (NSCLC) show prognostic heterogeneity. We aimed to assess the relationship of the number of metastatic lymph nodes (LNs) and zones with prognosis in NSCLC patients.

Methods: We analysed 1393 patients who underwent lobectomy with mediastinal LN dissection for NSCLC at the Osaka International Cancer Institute between January 2006 and December 2015. Patients were classified into 3 groups according to the number of LNs: n1-3, n4-6 and n7-. We investigated the relationship of prognosis with the number of metastatic LNs and metastatic zones.

Results: In the multivariable analyses, the number of metastatic LNs and zones were not independent factors for overall survival or recurrence-free survival in patients with pN1 disease after adjustment for age, sex, tumour histology and tumour diameter. However, n4-6 (ref. n1-3) was an independent prognostic factor for overall survival [hazard ratio (HR) 4.148, P < 0.001] in those with pN2 disease. There were no significant differences in overall survival and recurrence-free survival between pN1 (HR 0.674, P = 0.175) and pN2n1-3 disease (HR 1.056, P = 0.808). Moreover, patients with pN2 disease with a higher number of metastatic zones had a poor prognosis for recurrence-free survival [3 zones (ref. 1): HR 1.774, P = 0.051, and 4 zones (ref. 1): HR 2.173, P < 0.047].

Conclusions: The number of metastatic LNs and metastatic zones were useful prognostic factors in NSCLC patients. The findings could help in establishing a new pN classification.

Keywords: Lung cancer; Lymph node dissection; Tumour-node-metastasis staging system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Non-Small-Cell Lung / diagnosis
  • Carcinoma, Non-Small-Cell Lung / secondary*
  • Carcinoma, Non-Small-Cell Lung / surgery
  • Female
  • Humans
  • Lung Neoplasms / diagnosis*
  • Lung Neoplasms / surgery
  • Lymph Nodes / pathology*
  • Lymphatic Metastasis
  • Male
  • Mediastinum
  • Middle Aged
  • Neoplasm Staging*
  • Prognosis
  • Retrospective Studies
  • Young Adult