Type of lymph node involvement and survival in pathologic N1 stage III non-small cell lung carcinoma

Eighth Edition Staging of Thoracic Malignancies: Implications for the Reporting Pathologist

Context The Staging and Prognostic Factors Committee of the International Association for the Study of Lung Cancer, in conjunction with the International Mesothelioma Interest Group, the International Thymic Malignancy Interest Group, and the Worldwide Esophageal Cancer Collaboration, developed proposals for the 8th edition of their respective tumor, node, metastasis (TNM) staging classification systems. Objective To review these changes and discuss issues for the reporting pathologist. Data Sources Proposals were based on international databases of lung (N = 94 708), with an external validation using the US National Cancer Database; mesothelioma (N = 3519); thymic epithelial tumors (10 808); and epithelial cancers of the esophagus and esophagogastric junction (N = 22 654). Conclusions These proposals have been mostly accepted by the Union for International Cancer Control and the American Joint Committee on Cancer and incorporated into their respective staging manuals (2017). The Union for International Cancer Control recommended implementation beginning in January 2017; however, the American Joint Committee on Cancer has deferred deployment of the eighth TNM until January 1, 2018, to ensure appropriate infrastructure for data collection. This manuscript summarizes the updated staging of thoracic malignancies, specifically highlighting changes from the 7th edition that are relevant to pathologic staging. Histopathologists should become familiar with, and start to incorporate, the 8th edition staging in their daily reporting of thoracic cancers henceforth.

Prognostic impact of node involvement pattern in pN1 non-small cell lung cancer patients

INTRODUCTION

We previously showed that squamous cell carcinoma (SCC) patients with directly involved N1 nodes resulted in outcomes significantly better than those with separately involved N1 nodes. The purpose of this study was to evaluate the prognostic effect of node involvement patterns in pN1 non-small cell lung cancer (NSCLC) patients, with special attention given to any differences between SCC and adenocarcinoma (AD).

METHODS

We reviewed 324 consecutive patients with completely resected pN1 NSCLC and classified them into two groups based on their node involvement patterns: directly or separately involved N1 groups. To compare survival rates, 1545 pN0 patients and 330 pN2 patients were also investigated.

RESULTS

Univariate and multivariate analyses showed that the node involvement pattern was significantly associated with pN1 NSCLC patient outcome. The directly involved N1 group had a much better 5-year overall survival rate of 60.1% compared with 45.0% for the separately involved N1 group. In SCC patients, the directly involved N1 group showed an overall survival similar to pN0 patients, whereas overall survival of the separately involved N1 group was identical to that of pN2 patients, and their survival rates were significantly different. In AD patients, however, the survival rates were marginally different between the directly and separately involved N1 groups, and they were intermediate between pN0 and pN2 patient survival rates.

CONCLUSIONS

Node involvement patterns had significant prognostic effect in pN1 NSCLC patients. This effect was different between SCC and AD cases. The subclassification of N1 based on node involvement pattern is of significance for SCC patients but not for AD patients.

Prognostic significance of surgical-pathologic N1 lymph node involvement in non-small cell lung cancer

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.

The IASLC Lung Cancer Staging Project: Proposals for the Revision of the N Descriptors in the Forthcoming Seventh Edition of the TNM Classification for Lung Cancer

INTRODUCTION

Accurate staging of lymph node involvement is a critical aspect of the initial management of nonmetastatic non-small cell lung cancer (NSCLC). We sought to determine whether the current N descriptors should be maintained or revised for the next edition of the international lung cancer staging system.

METHODS

A retrospective international lung cancer database was developed and analyzed. Anatomical location of lymph node involvement was defined by the Naruke (for Japanese data) and American Thoracic Society (for non-Japanese data) nodal maps. Survival was calculated by the Kaplan-Meier method, and prognostic groups were assessed by Cox regression analysis.

RESULTS

Current N0 to N3 descriptors defined distinct prognostic groups for both clinical and pathologic staging. Exploratory analyses indicated that lymph node stations could be grouped together into six "zones": peripheral or hilar for N1, and upper or lower mediastinal, aortopulmonary, and subcarinal for N2 nodes. Among patients undergoing resection without induction therapy, there were three distinct prognostic groups: single-zone N1, multiple-zone N1 or single N2, and multiple-zone N2 disease. Nevertheless, there were insufficient data to determine whether the N descriptors should be subdivided (e.g., N1a, N1b, N2a, N2b).

CONCLUSIONS

Current N descriptors should be maintained in the NSCLC staging system. Prospective studies are needed to validate amalgamating lymph node stations into zones and subdividing N descriptors.

Survival and characteristics of lymph node involvement in patients with N1 non-small cell lung cancer

N1 non-small cell lung cancer (NSCLC) encompasses a heterogeneous subgroup with differential lymph node involvement. Among 738 patients with NSCLC who underwent surgical resection, including 579 patients (78.5%) with systematic hilar and mediastinal lymph nodal dissection, from 1992 to 2001, 82 patients were pathologically defined as having N1 disease. We retrospectively analyzed the factors influencing survival, including the characteristics of lymph node involvement; the location of involved stations, the number of involved stations, the number of involved nodes, and the status of nodal involvement (microscopic N1, nodal involvement first defined by postoperative histological examination; or macroscopic N1, nodal involvement obviously recognized by preoperative examinations or surgical explorations). The overall 5-year survival rate of the 82 patients with N1 disease was 50.9%. No significant differences in the overall survival were found with regard to gender, age, histologic type, type of resection, or adjuvant therapies. Pathologic T status significantly influenced the overall survival (T1 versus T2 disease, P=0.008). According to the characteristics of lymph node involvement, the prognosis of patients with multiple-node N1 involvement was significantly poorer than that of those with single-node N1 involvement (5-year survival: 29.6% versus 61.5%, p=0.003). The prognosis of patients with macroscopic N1 disease was significantly poorer than that of those with microscopic N1 disease (5-year survival: 43.0% versus 65.0%, P=0.046). By comparison with the survival of patients who underwent surgical resection during the same period for pathologic N0 (pN0) and pathologic N2 (pN2) diseases, no survival differences were observed between microscopic N1/single-node N1 and pN0, or between multiple-node N1 and pN2 diseases. In patients with pathologic N1 disease, microscopic N1 and single-node N1 diseases may be an early stage, whereas multiple-node N1 disease behaves like an advanced stage.

Pathologic N1 non-small cell lung cancer: correlation between pattern of lymphatic spread and prognosis

OBJECTIVES

Patients with N1 non-small cell lung cancer represent a heterogeneous population with varying long-term survivals. Prognosis and pattern of recurrence seem to be particularly affected by the level of lymph node involvement.

METHODS

From 1990 to 1995, a total of 1954 consecutive patients underwent surgical resection for non-small cell lung cancer: 549 (28%) had ipsilateral pulmonary lymph node metastases (N1). The hospital survivors (n = 535) were reviewed. Three levels of lymph node metastases (hilar, interlobar, and lobar) were identified according to the new Regional Lymph Node Classification for Lung Cancer Staging and differentiated from lymph node involvement on the basis of direct invasion.

RESULTS

1 The overall 5-year survival of patients with N1 disease was 40%. Survival was related in the univariate analysis to T classification, level-type of N1 involvement, number of involved nodes, multilevel involvement, Karnofsky Index, R status, and adjuvant therapy. In the multivariate analysis, only T classification and level-type of N1 involvement clearly showed statistical power (P =.000 and P =.001, respectively). The pattern of cancer relapse according to level-type of N1 involvement differed significantly: hilar N1 disease recurred at distant sites in 41% of patients and locoregionally in 12% of patients, whereas N1 disease by direct invasion occurred in 24% and 17% of patients, respectively (P =.030).

CONCLUSIONS

Metastases to ipsilateral hilar, interlobar, or both, lymph nodes are associated with a poorer prognosis compared with metastases in intralobar lymph nodes or with lymph node involvement by means of direct invasion. Although surgical resection remains the mainstay of treatment, the high rate of tumor recurrence in both groups mandates further randomized studies with multimodality therapy approaches.