Long-term survival after surgery for pulmonary metastases from colorectal cancer: an observational cohort study

Evidence for pulmonary metastasectomy following colorectal cancer (CRC) is scarce. The aim of the study was to investigate long-term survival and identify prognostic factors to aid patient selection.

We included all patients who underwent pulmonary resections for CRC metastases between January 01, 2004 and December 31, 2015 in a population-based cohort study. The primary outcome measure was all-cause mortality and was ascertained from Swedish national registers. The Kaplan-Meier estimator was used to calculate cumulative survival. We used Cox regression for estimation of hazard ratios (HR) and 95% confidence intervals (CI) for the association between patient characteristics and survival.

We included 184 patients. The number of procedures per year increased from 1 in 2004 to 34 in 2015. During a median follow-up time of 3.2 years, 36% (66/184) patients died. Overall survival at 5 years was 60% (95% CI: 50-68%) and was significantly lower compared to an age- and gender-matched Swedish population. Carcinoembryonic antigen (CEA) level was identified as a prognostic factor for mortality in the age and sex-adjusted analysis (HR, 2.46; 95% CI: 1.15-5.26, P=0.020).

We found a steady increase in the number of pulmonary metastasectomies after CRC during the study period. We identified prethoracotomy CEA level as a prognostic factor for long-term survival, which was consistent with prior reports. The 5-year overall survival rate in our study was 60%, which was high in comparison with prior reports. Although our results indicated that current patient selection criteria were reasonable, definitive evidence of efficacy is pending.