Prognostic impact of lymph node involvement in pulmonary metastases from colorectal cancer.

OBJECTIVE The purpose of this study was to identify the prognostic impact of unexpected lymph node metastases in patients undergoing resection of pulmonary metastases from colorectal cancer and specify the influence of pulmonary and mediastinal nodal involvement according to the modified Narukes lymph node mapping [Mountain CF, Dresler CM. Regional lymph node classification for lung cancer. Chest 1997;111(6):1718-23.]. METHODS From January 1993 to December 2003, 175 patients were diagnosed and resected for pulmonary metastases of colorectal cancer. Follow up informations were collected for 169 patients and an analysis of prognostic factors was performed. Ninety-six men (56.8%) and 73 women (43.2%) with a median age of 62 (range 34-81) were identified, 28 (16.7%) patients were found to have lymph node metastases, five of them were identified during a recurrent procedure. Probability of survival was calculated according to the method of Kaplan-Meier. The prognostic influence of lymph node metastases on survival was analyzed with the log-rank test. RESULTS Median survival was 47.2 months after first metastasectomy. Ten patients with intrapulmonary nodal involvement had a median survival of 86 months whereas 12 patients with hilar and six patients with mediastinal lymph node metastases had a median survival of 24.5 and 34.7 months. The survival difference between pulmonary and hilar/mediastinal metastases was statistically significant (p=0.008/p=0.07). Five year survival with pulmonary, hilar, and mediastinal metastases was 78.5, 0, and 0%, respectively. Perioperative mortality was 0%. CONCLUSIONS Resection of pulmonary metastases secondary to colorectal cancer is safe and indicated in highly selected patients. Because tumor involvement of lymph nodes has a strong impact on survival; depending on their location, at least a lymph node sampling should always be performed. Adjuvant chemotherapy in case of proven lymph node metastases might be a good option to improve prognosis.