Background: Utilization of evidence-based treatments for patients with colorectal liver metastasis (CRC-LM) outside high-volume centers is not well-characterized. We sought to describe trends in treatment and outcomes, and identify predictors of therapy within a nationwide integrated health system.
Methods: Observational cohort study of patients with CRC-LM treated within the Veterans Affairs (VA) health system (1998-2012). Secular trends and outcomes were compared on the basis of treatment type. Multivariate regression was used to identify predictors of no treatment (chemotherapy or surgery).
Results: Among 3270 patients, 57.3 % received treatment (chemotherapy and/or surgery) during the study period. The proportion receiving treatment doubled (38 % in 1998 vs. 68 % in 2012; trend test, p < 0.001), primarily driven by increased use of chemotherapy (26 vs. 57 %; trend test, p < 0.001). Among patients having surgery (16 %), the proportion having ablation (10 vs. 61.9 %; trend test, p < 0.001) and multimodality therapy (15 vs. 67 %; trend test, p < 0.001) increased significantly over time. Older patients [65-75 years: odds ratio (OR) 1.65, 95 % confidence interval (CI) 1.39-1.97; >75 years: OR 3.84, 95 % CI 3.13-4.69] and those with high comorbidity index (Charlson ≥3: OR 1.47, 95 % CI 1.16-1.85) were more likely to be untreated. Overall survival was significantly different based on treatment strategy (log-rank p < 0.001).
Conclusions: The proportion of CRC-LM patients receiving treatment within the largest integrated health system in the US (VA health system) has increased substantially over time; however, one in three patients still does not receive any treatment. Future initiatives should focus on increasing treatment among older patients as well as on evaluating reasons leading to the no-treatment approach and increased use of ablation procedures.