Recurrence-free survival curve for pulmonary metastasectomy in colorectal cancer plateaus at 3 years.

Pulmonary metastasectomy in colorectal cancer (CRC) has encouraging results; however, specific criteria for lung resection and the timing of resection remain undetermined. Therefore, in this study, we aimed to examine the long-term prognosis and 10-year survival rates and analyze poor prognostic factors in patients who underwent resection of pulmonary metastases from CRC. This retrospective, single-institution study included 156 patients with controlled primary CRC and metastases confined to the lungs or liver who underwent pulmonary metastasectomy between 2005 and 2022. Statistical analyses were conducted using the X² and two-tailed Student's t test to compare variables. The receiver operating characteristic (ROC) curve was used to determine the appropriate cut-off point for tumor size as a predictive factor of survival. Recurrence-free survival (RFS) and overall survival (OS) were estimated using the Kaplan-Meier method, and non-parametric group comparisons were performed using log-rank tests. The 5- and 10-year OS rates were 67% and 59%, respectively. Further, there was no recurrence 38 months post-surgery, and the RFS curve plateaued. Moreover, by 88 months post-surgery, no deaths occurred, and the OS curve plateaued. Multivariate analysis revealed that a pulmonary metastatic tumor >14 mm and disease-free interval <2 years indicated poor prognosis. The RFS curve for pulmonary metastasectomy may plateau approximately 3 years after surgery. Pulmonary metastasectomy can achieve long-term survival in selected patients with CRC. Furthermore, surgical resection of recurrence after pulmonary metastasectomy may lead to better results. Thus, tumor size and disease-free interval may be independent prognostic factors.