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

Abstract

Importance: Research 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.

Objective: To investigate the incidence and risk factors associated with BO in patients with stage IV colon cancer.

Design and setting: Retrospective 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.

Results: We 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.

Figure. Cumulative Incidence of Hospitalization for Bowel Obstruction Over Time

Cumulative incidence of hospitalization for bowel obstruction over time in the baseline cohort of 12 553 patients with stage IV colon cancer in the Surveillance, Epidemiology, and End Results and Medicare claims linked databases for January 1, 1991, through December 31, 2005, stratified by tumor histological type. For reference, the median survival of each group is given. We found no significant difference in survival experience by histological type (P = .29) in a multivariable model of survival since the cancer diagnosis that included age at and year of diagnosis, sex, marital status, patient comorbidity score, primary tumor surgery, chemotherapy after diagnosis, tumor site and grade, and lymph node status. IQR indicates interquartile range.