U.S. Hospitalizations for Colorectal Cancer: 1970-2010

Abstract

Purpose: The occurrence of colorectal cancer appears to be declining in the United States. The aim of the present study was to confirm such time trends using hospitalization data for colorectal cancer from the past four decades. Methods: U.S. hospital utilization data were available for individual years from 1970-2010 through the National Hospital Discharge Survey. Colon and rectum cancer were analyzed separately, stratified by their ICD-9CM codes and listing as first (primary) versus secondary hospital discharge diagnosis. Hospitalizations during consecutive five-year periods were expressed as annual rates per 100,000 living U.S. population. Two rates with their respective standard errors were compared using a z-statistic. Results: During the most recent time period, 2006-2010, colon cancer was associated with 177,000, and rectum cancer with 76,000 annual hospitalizations; that is, 58, and 25 hospitalizations per 100,000 US population. In 59% and 55% of these instances, respectively, colon and rectum cancer were listed as the primary discharge diagnosis. First and all-listed colorectal cancers were characterized by similar time trends. After an initial rise of colon cancer listed as primary diagnosis between 1970 and 1985 from 41 to 65 annual hospitalization per 100,000, it declined to currently 30 per 100,000. In rectum cancer, the corresponding rates were 19, 24, and 13 hospitalizations per 100,000, respectively. The rise and fall of both cancer types were statistically significant (p<0.001). Similar trends were also found in men and women analyzed separately for both cancer types. When analyzed in an age-specific fashion, in both cancer types alike, the recent decline became most pronounced in the 65 years and older age group, and to a lesser degree in the 45-64 years age group, with p<0.001 for both age groups. It was not statistically significant in the younger age groups. Conclusion: Hospitalizations for colorectal cancer have declined in the United States since the mid-1980s. The onset of this decline preceded the widespread use of screening for colorectal cancer. Other mechanisms besides screening may have contributed to this observed decline.