Original article
General thoracic
Prognostic Significance of Surgical-Pathologic N1 Lymph Node Involvement in Non-Small Cell Lung Cancer

https://doi.org/10.1016/j.athoracsur.2008.12.053Get rights and content

Background

Patients with N1 non-small cell lung cancer represent a heterogeneous population with varying long-term survival. To better define the importance of N1 disease and its subgroups in non-small cell lung cancer staging, we analyzed patients with N1 disease using the sixth edition and proposed seventh edition TNM classifications.

Methods

From January 1995 to November 2006, 540 patients with N1 non-small cell lung cancer who had at least lobectomy with systematic mediastinal lymphadenectomy were analyzed retrospectively.

Results

For completely resected patients, the median survival rate and 5-year survival rate were 63 months and 50.3%, respectively. The 5-year survival rates for patients with hilar N1 (station 10), interlobar (station 11), and peripheral N1 (stations 12 to 14) involvement were 39%, 51%, and 53%, respectively. Patients with hilar lymph node metastasis showed a shorter survival period than patients with peripheral lymph node involvement (p = 0.02). Patients with hilar zone N1 (stations 10 and 11) involvement tended to show poorer survival than patients with peripheral zone N1 (12 to 14) metastasis (p = 0.08). Multiple-station lymph node metastasis indicated a poorer prognosis than single-station involvement (5-year survival 39% versus 51%, respectively, p = 0.01). Patients with multiple-zone N1 involvement showed poorer survival than patients with single-zone N1 metastasis (p = 0.04). A significant survival difference was observed between N1 patients with T1a versus T1b tumors (p = 0.02). Multivariate analysis revealed that only multiple-station lymph node metastasis was predictive of poor prognosis (p = 0.05).

Conclusions

Multiple-station versus single-station N1 disease and multiple-zone versus single-zone N1 involvement indicate poorer survival rate. Patients with hilar lymph node involvement had lower survival rates than patients with peripheral N1. The impact of T factor seemed to be veiled by the heterogenous nature of N1 disease. Further studies of adjusted postoperative strategies for different N1 subgroups are warranted.

Section snippets

Patients and Methods

From January 1995 to November 2006, we performed 1,616 anatomic resections in patients with NSCLC in our institution. Patients were grouped according to highest level of involved lymph node station. Of these, 862 patients (53.3%) had no nodal metastases (N0 disease), 540 (33.4%) had N1 nodal metastases (N1 disease), and 214 (13.2%) had mediastinal nodal metastases (N2 disease). We performed retrospective analysis of the pattern of lymph node metastasis and prognosis in 540 consecutive

Results

The completely resected patients had a 5-year survival rate of 50.3% with a median survival time of 63 months; incompletely resected patients had a 5-year survival rate of 19% with a median survival time of 23 months (p = 0.003; Fig 1). The 5-year survival rates of patients with squamous cell carcinoma, adenocarcinoma, and others were 50%, 51%, and 43%, respectively. Although squamous cell carcinoma tended to show a better prognosis, no significant difference was observed among the three

Comment

The accurate staging of lymph node involvement is of pivotal importance in the management of NSCLC as it aids in treatment selection and predicting outcome [2]. In patients undergoing surgery for resection of NSCLC, the assessment of nodal disease has gradually become an accepted part of the operation [2].

The latest revisions of the TNM staging system were adopted in 1997 [1]. These consisted of stage grouping by a recombination of T, N, and M factors, and redefinition of these factors. In the

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