Pulmonary resection for colorectal cancer metastases: Duration between cancer onset and lung metastasis as an important prognostic factor

Background: Pulmonary resection is the most effective treatment available for colorectal lung metastases. However, the characteristics of those patients most likely to benefit from surgical resection have not yet been adequately clarified. We have made a critical analysis for the potential prognostic factors and their clinical significance in lung metastasis from colorectal cancer. Methods: We analyzed 63 consecutive patients who underwent curative pulmonary resection for colorectal lung metastases at National Taiwan University Hospital from January 1997 to December 2006. Median follow-up was 37.3 (range 12-122) months. Disease-free and overall survival rates were evaluated by Kaplan-Meier analysis, and multivariate analyses of various prognostic characteristics were performed. Results: Overall 5-year survival and disease-free survival rates were 43.9% and 19.5%, respectively. Multivariate analysis showed that the interval for development of lung metastases from primary colorectal cancer and the mode of operation were the only two independent prognostic factors for survival. With regard to disease-free survival, the interval between initial resection of colorectal cancer and following lung metastases was the only significant independent prognostic factor. Besides, subset analysis showed that the 5-year survival rate in repeated resection group for recurrence of colorectal metastasis in residual lung was 85.7%. Conclusion: Pulmonary resection, initial or even repeated resection for metastatic tumor from colorectal cancer should be encouraged for selected patients as it can significantly improve survival. Patients who have lung metastases within 1 year after primary tumor resection and those who do not undergo anatomical resection for metastatic lung tumor should be followed more carefully due to poor prognosis.