A Real-World, Population-Based Analysis of the Outcomes of Colorectal Cancer Patients with Isolated Synchronous Liver or Lung Metastases Treated with Metastasectomy.

OBJECTIVE: To assess the survival outcomes among a contemporary cohort of colorectal cancer patients with isolated synchronous liver or lung metastases treated with or without surgical resection of the metastases.

METHODS: Surveillance, epidemiology and end results database has been accessed and cases with isolated liver or lung metastases diagnosed 2010-2015 have been accessed. Kaplan-Meier survival estimates were used to compare overall survival among patients who had or had not undergone metastasectomy. Multivariable Cox regression analysis was then used to assess the impact of metastasectomy on colorectal cancer-specific survival.

RESULTS: A total of 16,372 patients with colorectal cancer with isolated liver or lung metastases (M1a disease) were included in the current analysis (including 14,832 patients with isolated liver metastases and 1540 patients with isolated lung metastases). Patients who had undergone surgical resection of liver metastases have better overall survival compared to patients who had not undergone surgical resection of liver metastases (median overall survival: 38.0 months vs. 13.0 months; P < 0.001). Likewise, patients who had undergone surgical resection of lung metastases have better overall survival compared to patients who had not undergone surgical resection of lung metastases (median overall survival: 45.0 months vs. 19.0 months; P < 0.001). In a multivariable Cox regression analysis and among patients with isolated liver metastases, surgery to the metastases was associated with a reduced hazard of death (hazard ratio (HR) 0.567; 95% CI 0.529-0.609; P < 0.001). Likewise, and among patients with isolated lung metastases, surgery to the metastases was associated with a reduced hazard of death (HR 0.482; 95% CI 0.349-0.665; P < 0.001).

CONCLUSION: In a contemporary cohort, metastasectomy seems to be associated with improvement in overall and cancer-specific survival among patients with isolated synchronous liver or lung metastases from colorectal cancer. Whether this survival difference is totally ascribed to the effect of metastasectomy or it is the fact that patients who were eligible for surgical resection have limited disease extent and better medical profile (thus, leading to better survival) is unclear from such a population-based study.