Trends in Incidence and Stage at Diagnosis of Colorectal Cancer in Adults Aged 40 Through 49 Years, 1975-2015

Abstract

This cancer epidemiology study uses SEER program data to describe trends in stage of incident colorectal cancer in adults aged 40-49 years between 1975 and 2015 to understand if apparent increases in incidence are due to earlier detection or true increases in risk.

Figure 1.. Trends in Colorectal Cancer (CRC) Incidence by Stage in Adults Aged 40 Through 49 Years

Data are from the Surveillance, Epidemiology, and End Results program and were age-standardized to the 2000 US standard population. Solid lines represent fitted piecewise–log linear trends. Average annual percentage changes (AAPCs) with parametric confidence intervals were calculated from 1995, when incidence started to increase. ^aStatistically significantly different from zero at 95% significance thresholds.

Figure 2.. Shift in Stage Distribution of Colorectal Cancers (CRCs) Diagnosed in Adults Aged 40 Through 49 Years^a

^aData are from the Surveillance, Epidemiology, and End Results program. 95% Confidence intervals were derived using the Sison-Glaz method for multinomial data. Statistical tests (2-sided Pearson χ²) assessed the stage-specific changes in proportions from 1990-1994 to 2011-2015. The differential relative increase by stage in the overall stage distribution was P<.001. Error bars indicate 95% CIs.