Abstract
Background Colorectal cancer (CRC) incidence and mortality has been declining in the U.S. Despite success in reducing CRC incidence, incidence of early-onset CRC has increased markedly. In this study, we identified age-related disparities in CRC incidence and mortality, and investigated differences in anatomical distribution of colon cancers between populations. Methods CRC trends were evaluated using Surveillance, Epidemiology, and End Results Program Data from 1980–2016 for individuals under age 50 and 50 years and older. Rates and ratios were calculated using SEER∗Stat. Regression analyses were calculated using Joinpoint. Results Increased CRC incidence among individuals under age 50 was observed. Among individuals under age 50, incidence-based mortality (IBM) stabilized, while incidence and IBM decreased for individuals aged 50 years and older. Normalized trends indicated increased rectal cancer incidence for individuals under age 50, particularly among individuals aged 30–39. Similar incidence of proximal and distal colon cancers in individuals under age 50 was observed, while colon cancers in individuals aged 50 and older were primarily distal. Conclusions We found age-related disparities in CRC incidence and IBM between individuals under age 50 and age 50 years and older. Increasing incidence rates of rectal cancer substantially accounts for this disparity among individuals under age 50. The escalating trends of early-onset CRC warrant investigation into the factors leading to the population-level trends.
Highlights
Colorectal cancer (CRC) incidence and mortality has been declining in the United States for over a decade
early-onset colorectal cancers (EOCRCs) is de ned as a cancer diagnosis occurring in individuals under the current recommended screening age of 50 [8]. ough substantial e orts have been directed towards the identi cation and understanding of the underlying genetics of hereditary CRC and recommendations are in place to screen individuals with a familial history of the disease, those presenting with sporadic CRC are typically missed by screening [9, 10]
Among those under the age of 50, age-adjusted incidence rates for colon cancer declined by 0.9% annually (95% con dence interval (CI): −1.6%, 0.2%) between 1980 and 1996, rates increased by 1.3% annually between 1996 and 2016 (Figure 1(a))
Summary
Colorectal cancer (CRC) incidence and mortality has been declining in the United States for over a decade. Siegel and colleagues investigated this phenomenon using Surveillance, Epidemiology, and End Results (SEER) Program Data and found that CRC rates have been increasing annually in individuals aged 20–39 and 40–54 since the mid-1980s and mid-1990s, respectively [15]. Ough not as Journal of Cancer Epidemiology drastic, similar trends have been observed for mortality in these age groups [16, 18]. We identi ed age-related disparities in CRC incidence and mortality, and investigated di erences in anatomical distribution of colon cancers between populations. CRC trends were evaluated using Surveillance, Epidemiology, and End Results Program Data from 1980–2016 for individuals under age 50 and 50 years and older. Increasing incidence rates of rectal cancer substantially accounts for this disparity among individuals under age 50. Increasing incidence rates of rectal cancer substantially accounts for this disparity among individuals under age 50. e escalating trends of early-onset CRC warrant investigation into the factors leading to the population-level trends
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