Trends in Colorectal Cancer Incidence and Survival in Iowa SEER Data: The Timing of It All

Colorectal cancer is common worldwide. Our results indicated that both overall and older onset colorectal cancer incidence began to decline in the early 2000s, whereas younger onset incidences decreased until the late 1980s but then increased steeply through the 2000s. These and other results suggested that regular colorectal screenings could reduce incidence and mortality in people under 50. Background: Colorectal cancer (CRC) is common worldwide, with 140,250 diagnoses and 50,630 deaths estimated for the United States in 2018. Guidelines current to the most recent individuals in our analysis suggested regular screenings beginning at age 50 have reduced the incidence of CRC. However, the incidence continues to rise among those under 50. Less is known about survival following CRC diagnosis, but research has suggested that younger cases may also have worse survival. However, we hypothesize that younger individuals are generally healthier with fewer comorbidities, leading to the potential for better survival following diagnosis. Materials and Methods: We utilized the Surveillance, Epidemiology, and End Results data to estimate and assess both spatial and temporal variation in age-specific colorectal cancer incidence and survival in Iowa. Results: Both overall and older-onset colorectal cancer incidence began to decline in the early 2000s, whereas younger-onset incidences decreased until the late 1980s but then increased steeply through the 2000s. The risk for those younger than 50 years of age first exceeded the risk for those 50 years or older in 2007. Survival times did increase for overall CRC, older-onset CRC, and young-onset CRC throughout the study period, with young-onset CRC increasing at a higher rate. The spatial variation assessment indicated that the survival was positively associated with several variables of interest, most notably disparities including better access to healthcare and higher sociodemographic status. Conclusion: In conclusion, results suggest that regular colorectal screenings could reduce incidence and mortality in people under 50. (C) 2018 Elsevier Inc. All rights reserved.