Liver Metastases and Survival Among Patients With Colorectal Cancer.

Importance: Colorectal liver metastases (CRLM) are a major cause of death in patients with colorectal cancer (CRC). Understanding patterns of incidence and survival is important to inform clinical care and policy. Objective: To examine temporal patterns of incidence, characteristics, and survival among patients with synchronous and metachronous CRLM. Design, Setting, and Participants: This population-based cohort study in Denmark used Danish national health registries, including the Cancer Registry, National Patient Registry, and National Pathology Registry, as data sources. A nested medical record review of a subset of patients (n = 954) was also conducted to assess concordance in incidence between registry data and medical records. All patients diagnosed with CRLM in Denmark between 2007 and 2024 were included. Main Outcomes and Measures: The end points were the cumulative incidence of CRLM from the date of CRC diagnosis (calculated at 1, 3, and 5 years of follow-up) and overall survival from the date of CRLM diagnosis (estimated using Kaplan-Meier curves and Cox proportional hazards regression models). Hazard ratios with 95% CIs were used to compare survival across diagnosis periods and CRLM subtypes (synchronous, early metachronous, and late metachronous). Results: A total of 14 785 patients with CRLM (median [IQR] age, 68.9 [62.2-77.0] years; 8616 males [58.3%]) were identified. The 5-year cumulative incidence of CRLM in patients with CRC was 19.8% (95% CI, 19.5%-20.1%). The cumulative incidence of CRLM decreased with age but was highest in patients younger than 50 years (5-year follow-up: 27.2%; 95% CI, 25.6%-28.8%); it was also highest in male patients (5-year follow-up: 21.5%; 95% CI, 21.1%-22.0%). The medical record review showed 26.2% (250 of 954) of patients developed CRLM during the follow-up period. One-year survival increased for patients with synchronous CRLM from 47.2% (95% CI, 45.3%-49.1%) in the 2007-2010 diagnosis period to 58.3% (95% CI, 54.1%-62.3%) in the 2020-2024 diagnosis period. Five-year survival also improved for patients with synchronous CRLM from 13.0% (95% CI, 11.7%-14.3%) in the 2007-2010 period to 20.7% (95% CI, 18.1%-23.5%) in the 2020-2024 period. No improvement was observed for either early or late metachronous CRLM. Conclusions and Relevance: In this cohort study, over time the cumulative incidence of CRLM decreased across all age groups, while survival increased for patients with synchronous and early metachronous CRLM but not for patients with late metachronous disease. These findings may reflect differences in tumor biology, comorbidity burden, and treatment eligibility and may support targeted follow-up and treatment strategies based on the timing of metastasis.