Long-term outcomes and early recurrence after resection for metachronous pulmonary metastases from colorectal cancer

Purpose Properly selecting patients for aggressive curative resection for pulmonary metastases (PMs) from colorectal cancer (CRC) is desirable. We purposed to clarify prognostic factors and risk factors for early recurrence after metachronous PM resection.Methods Clinical data of 151 patients who underwent R0 resection for metachronous PMs from CRC at two institutions between 2008 and 2021 were reviewed.Results Seventy-six patients (50.3%) were male, and the median age was 71 (42-91) years. The numbers of colon/rectal cancers were 76/75, with pStage I/II/III/IV/unknown in 15/34/86/13/3. The duration from primary surgery to PM was 19.7 (1.0-106.4) months. The follow-up period was 41.9 (0.3-156.2) months. The 1-, 3-, and 5-year recurrence-free survival (RFS) rates were 75.1%, 53.7%, and 51.1%, and the 1-, 3-, and 5-year overall survival (OS) rates were 97.7%, 87.5%, and 68.2%. On multivariate analysis, lymph node metastasis of the primary lesion (HR 1.683, 95%CI 1.003-2.824, p = 0.049) was an independent predictor of poor RFS, and history of resection for extrapulmonary metastasis (e-PM) (HR 2.328, 95%CI 1.139-4.761, p = 0.021) was an independent predictor of poor OS. Patients who experienced early recurrence (< 6 months) after PM resection showed poorer OS than others (3-year OS 50.8% vs. 90.2%, p = 0.002). On multivariate analysis, e-PM was an independent predictor of early recurrence after PM resection (OR 3.989, 95%CI 1.002-15.885, p = 0.049).Conclusion Since a history of e-PM was a predictor of early recurrence and poor OS after R0 resection for PM, surgical treatment of patients with a history of e-PM should be considered carefully.