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

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.

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.

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).

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.