This study investigated recent clinical outcomes and prognostic factors of metastasectomy for pulmonary metastasis (PM) from colorectal cancer.

Data for 785 patients with PM from colorectal cancer who underwent curative resection, including 376 patients treated with postmetastasectomy adjuvant chemotherapy, between 2004 and 2008, were collected from 46 Japanese hospitals. Disease-free and overall survival was analyzed. Potential prognostic factors were assessed.

The 5-year disease-free and overall survival rates (95% confidence interval) of all patients were 37.1% (33.7% to 40.9%) and 68.1% (64.6% to 71.8%), respectively, over a median follow-up of 65 months. On multivariable analysis, no survival benefit for postmetastasectomy adjuvant chemotherapy was observed (hazard ratio, 0.85; 95% confidence interval, 0.65 to 1.12; p = 0.25), and the independent poor prognostic factors for overall survival (hazard ratio, 95% confidence interval) were age 70 years and older (1.50, 1.15 to 1.97), disease-free interval of less than 2 years (1.76, 1.31 to 2.35), extrathoracic metastatic lesion treated curatively before PM resection (1.35, 1.01 to 1.79), abnormal carcinoembryonic antigen level (1.99, 1.53 to 2.58), and three or more PMs (1.72, 1.20 to 2.45). The 5-year overall survival rates (95% confidence interval) of the low-risk (no prognostic factor, n = 87), moderate-risk (1 to 2 factors, n = 539), and high-risk (≥3 factors, n = 159) groups were 89.4% (82.2% to 98.2%), 72.5% (68.3% to 76.8%), and 48.9% (41.7% to 57.3%), respectively.

Metastasectomy of PM from colorectal cancer was associated with a favorable prognosis. Patients could be classified into three risk groups using five prognostic factors. This grouping may be useful for identifying an optimal treatment strategy according to risk in future studies.