The first site of recurrence after complete resection in non-small-cell carcinoma of the lung. Comparison between pN0 disease and pN2 disease

In the present study, we assessed whether the pattern of postoperative recurrence of non-small-cell lung cancer differed between patients with pathologic N0 disease and those with pathologic N2 disease. We reviewed 231 patients with pathologic N0 disease and 63 with pathologic N2 disease, who had undergone a complete resection from 1980 to 1990, and investigated the first recurrence sites. Seventy-two patients with pathologic N0 disease and 52 with pathologic N2 disease were found to have had postoperative recurrence. Both pathologic N0 disease and pathologic N2 disease recur frequently in distant organs, and the ratio of distant metastasis to local recurrence did not differ between the two diseases. The brain, lung, and bone were the common initial metastatic sites in both pathologic N0 disease and pathologic N2 disease. The brain was the most frequent site of distant metastasis in patients with pathologic N0 disease, whereas, on the other hand, pulmonary metastasis was observed more frequently than brain metastasis in those with pathologic N2 disease. Despite histologic types, the presence of different patterns of initial metastatic sites between pathologic N0 and pathologic N2 diseases was observed. Our results suggest that the sites of metastasis after resection depend largely on such anatomic factors as drainage routes. Namely, in contrast to pathologic N0 disease, pathologic N2 disease has an additional drainage route, which is from the N2 nodes to the superior vena cava (pulmonary circulation). Therefore, the frequency of pulmonary metastasis may increase in patients with pathologic N2 disease.