University of Texas Southwestern Medical Center Dallas, TX
Introduction: Incidence rates of colorectal cancer (CRC) are increasing among younger adults (age < 50 years) in the U.S., and more recently, rates have increased in persons age 50-54 years. To better understand the corresponding changes in mortality, we examined trends in CRC mortality rates by age over a 27-year time period.
Methods: We used population-based data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results program of cancer registries to estimate age-specific (30-84 years, by 5-year age group) mortality rates per 100,000 persons during the period 1992–2019. We used joinpoint regression analysis to quantify changes in the direction and magnitude of mortality rates; the slope of the best-fit line between joinpoints corresponds to the annual percent change (APC) in mortality, with p< 0.05 indicating a statistically significant difference from a slope of zero.
Results: Between 1992 and 2019, CRC mortality rates steadily increased by about 1% per year for ages 30-34 and 35-39 years. For ages 40-44 and 45-49 years, rates decreased by < 1% per year from 1992 until the mid 2000s and subsequently increased from 2004 to 2019 (APC 1.1, p< 0.05) and 2006 to 2019 (APC 1.3, p< 0.05), respectively (Table 1). For age groups 50-54 to 60-64 years, mortality rates decreased by about 2% per year from 1992 until the mid 2000s; however, after 2006, rates increased for age 50-54 years (APC 0.5, p< 0.05) and decreased more slowly for ages 55-59 (APC -0.4, p< 0.05) and 60-64 (APC -1.5, p< 0.05) years. Mortality rates also decreased at a lower rate for age 65-69 years, beginning in 2011 (APC for 2011-2019: -1.7, p< 0.05 vs. APC for 2001-2010: -3.9, p< 0.05). For age groups 70-74 to 80-84 years, mortality rates steadily decreased by about 3% per year from 2000 to 2019.
Discussion: Age-specific CRC mortality rates mirror the well-described trends in CRC incidence rates, with increasing rates in every age group up to 50-54 years and slowing rates at age 55-59 years. Our findings suggest that CRC diagnoses and deaths are increasingly common in middle-aged adults, despite the availability of screening and improved treatment options. Future efforts should identify factors contributing to increasing CRC mortality rates, as well as implement strategies to improve screening participation in these age groups.
