Comorbidity and age as predictors of risk for early mortality of male and female colon carcinoma patients: a population-based study.

BACKGROUND: Colon carcinoma primarily affects persons 65 years and older. Seventy-five percent of the incident tumors affect persons in this age group. Because of their advanced age, older patients already may be coping with other concomitant major physical illnesses. This article documents preexisting diseases in older colon carcinoma patients at diagnosis and evaluates the effects of their comorbidity burden on early mortality. METHODS: Prevalence of comorbid conditions was assessed by a retrospective medical records review of an age-stratified random sample of male and female patients aged 55-64 years, 65-74 years, and 75+ years (males, n=799; females, n=811). Data were collected on comorbidity by the National Institute on Aging (NIA) and National Cancer Institute (NCI) and merged with NCI Surveillance, Epidemiology, and End Results (SEER) tumor registry data. RESULTS: Hypertension, high impact heart conditions, gastrointestinal problems, arthritis, and chronic obstructive pulmonary disease emerged as the most prominent comorbid conditions in the NIA/NCI SEER Study sample. The prevalence of comorbidity in the number and type of conditions was similar for both men and women (e.g., 40% of each gender had > or = 5 comorbidities). Within 2 years of diagnosis, 28% (n=454) of the patients had died. The number of comorbid conditions was significant in predicting early mortality in a model including age, gender, and disease stage (P=0.0007). Certain comorbidities, classified as "current problem," added significantly to a basic model (e.g., heart problems, alcohol abuse, liver disease, and deep vein thrombosis). CONCLUSIONS: Although disease stage at time of diagnosis of colon carcinoma is a crucial determinant of patient outcome, comorbidity increases the complexity of cancer management and affects survival duration. Cancer control and treatment research questions should address comorbidity issues pertinent to the age group primarily afflicted with colon carcinoma (i.e., the elderly).