Background: Clinical trials dealing with multimodal strategy for N2 non-small cell lung cancer are now being watched with keen interest, and the feasibility of this strategy is to be confirmed. N2 lung cancer, however, is composed of several subgroups with different prognoses. The prognostic factors still remain controversial.
Methods: Between January 1986 and July 1997, 222 patients with lung cancer underwent surgical intervention at our institute; these patients were eventually given a diagnosis of metastasis to ipsilateral mediastinal lymph nodes. All patients underwent mediastinal lymph node dissection or sampling. Sixteen clinicopathologic factors were investigated by univariable and multivariable analyses to identify significant prognostic factors among resected N2 disease. Clinical N status was evaluated by computed tomographic scan.
Results: The overall 5-year survival was 27%. Multivariable analyses among overall patients revealed 4 significant prognostic factors (P <.05): clinical N2 status, incomplete resection, larger tumor size, and multiple diseased N2 nodes. Based on the result, 32 patients with both clinical N2 status and pathologic multiple N2 nodes showed a 5-year survival of 5%, whereas 76 patients with neither of the factors showed a 5-year survival of 57% (P <.001).
Conclusion: The prognosis of surgically resected N2 disease varies tremendously according to the 4 significant prognostic factors. These factors should be clearly described in reporting clinical trials on N2 lung cancer. Clinical N status evaluated by computed tomographic scan should be 1 criterion to perform a clinical trial for N2 disease among a homogeneous population with respect to prognosis.