Incidence and predictors of bowel obstruction in elderly patients with stage IV colon cancer: a population-based cohort study.

importanceResearch has been limited on the incidence, mechanisms, etiology, and treatment of symptoms that require palliation in patients with terminal cancer. Bowel obstruction (BO) is a common complication of advanced abdominal cancer, including colon cancer, for which small, single-institution studies have suggested an incidence rate of 15% to 29%. Large population-based studies examining the incidence or risk factors associated with BO in cancer are lacking.

objectiveTo investigate the incidence and risk factors associated with BO in patients with stage IV colon cancer. DESIGN AND

settingRetrospective cohort, population-based study of patients in the Surveillance, Epidemiology, and End Results and Medicare claims linked databases who were diagnosed as having stage IV colon cancer from January 1, 1991, through December 31, 2005. PATIENTS: Patients 65 years or older with stage IV colon cancer (n = 12 553). MAIN OUTCOMES AND MEASURES: Time to BO, defined by inpatient hospitalization for BO. We used Cox proportional hazards regression models to determine associations between BO and patient, prior treatment, and tumor features.

resultsWe identified 1004 patients with stage IV colon cancer subsequently hospitalized with BO (8.0%). In multivariable analysis, proximal tumor site (hazard ratio, 1.22 [95% CI, 1.07-1.40]), high tumor grade (1.34 [1.16-1.55]), mucinous histological type (1.27 [1.08-1.50]), and nodal stage N2 (1.52 [1.26-1.84]) were associated with increased risk of BO, as was the presence of obstruction at cancer diagnosis (1.75 [1.47-2.04]). A more recent diagnosis was associated with decreased risk of subsequent obstruction (hazard ratio, 0.84 [95% CI, 0.72-0.98]). CONCLUSIONS AND RELEVANCE: In this large population of patients with stage IV colon cancer, BO after diagnosis was less common (8.0%) than previously reported. Risk was associated with site and histological type of the primary tumor. Future studies will explore management and outcomes in this serious, common complication.