Background: Although routine systematic mediastinal and hilar lymph node dissection contemporary with pulmonary metastasectomy has not been uniformly performed in many thoracic surgical centers, the value of this procedure needs to be investigated.
Methods: Between 1996 and 2001, 245 patients (157 men, 88 women) underwent pulmonary resection of metastatic colorectal carcinoma, sarcoma, and renal cell carcinoma. Generally, systematic mediastinal and hilar lymph node dissection was performed concurrently with pulmonary metastasectomy. Patients were assessed for patterns of lymph node metastases. The frequency of lymph node involvement was determined. Patients and tumor characteristics were assessed to ascertain whether certain factors were likely to predict lymph node spread.
Results: Of the 245 patients (328 primary thoracic procedures), 165 had no lymph node involvement, 45 had pulmonary and hilar metastases, 22 had pulmonary, hilar, and mediastinal metastases, and 13 had only mediastinal involvement without pulmonary and hilar spread. Patients with more than one pulmonary metastasis or metachronous disease were more likely to have thoracic lymph node metastases. The risk for mediastinal lymph node involvement was even more likely for patients who had already pulmonary or hilar lymph node spread; the odds ratios (with 95% confidence intervals) were 1.30 (0.71 to 2.36), 1.32 (0.59 to 2.99), and 5.87 (2.73 to 12.6), respectively. Median survival for the group of patients after complete resection was 54.8 months (95% CI: 40.9 to 68.7); and for the patients with no lymph node involvement, it was 63.9 months (95% CI: 45.3 to 82.6); with N1 disease, 32.7 months (95% CI: 9.2 to 56.2); and with N1 + N2 disease, 20.6 months (95% CI: 5.1 to 36.1). The log-rank test revealed significance between N0 and N1 (p = 0.018) and N0 versus N1, 2 (p = 0.001).
Conclusions: We conclude that systematic mediastinal and hilar lymph node dissection contemporary with pulmonary metastasectomy offers a further understanding of metastatic disease and provides important information for complete surgical staging.