Improving treatment and survival: a population-based study of current outcomes after a hepatic resection in patients with metastatic colorectal cancer.

Background: Population-based studies historically report underutilization of a resection in patients with colorectal metastases to the liver. Recent data suggest limitations of the methods in the historical analysis. The present study examines trends in a hepatic resection and survival among Medicare recipients with hepatic metastases.

Methods: Medicare recipients with incident colorectal cancer diagnosed between 1991 and 2009 were identified in the SEER(Surveillance, Epidemiology and End Results)-Medicare dataset. Patients were stratified into historical (1991-2001) and current (2002-2009) cohorts. Analyses compared treatment, peri-operative outcomes and survival.

Results: Of 31.574 patients with metastatic colorectal cancer to the liver, 14,859 were in the current cohort treated after 2002 and 16,715 comprised the historical control group. The overall proportion treated with a hepatic resection increased significantly during the study period (P < 0.001) with pre/post change from 6.5% pre-2002 to 7.5% currently (P < 0.001). Over time, haemorrhagic and infectious complications declined (both P ≤ 0.047), but 30-day mortality was similar (3.5% versus 3.9%, P = 0.660). After adjusting for predictors of survival, the use of a hepatic resection [hazard ratio (HR) = 0.40, 95% confidence interval (CI): 0.38-0.42, P < 0.001] and treatment after 2002 (HR = 0.88, 95% CI: 0.86-0.90, P < 0.001) were associated with a reduced risk of death.

Conclusions: Case identification using International Classification of Diseases, 9th Revision (ICD-9) codes is imperfect; however, comparison of trends over time suggests an improvement in multimodality therapy and survival in patients with colorectal metastases to the liver.