Objectives: The past decade has witnessed important advances in colorectal cancer (CRC) screening and treatment. To assess the potential impact of these advances on CRC survival and incidence, we evaluated recent temporal trends in the United States.
Methods: Using the nine population-based cancer registries that constitute the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute, we identified primary CRCs diagnosed between 1986 and 1997. Temporal changes were evaluated for the periods 1986-1988, 1989-1991, 1992-1994, and 1995-1997. Age-adjusted incidence and relative 1-, 3-, and 5-yr survival were calculated, along with 95% CI.
Results: We identified 144,284 individuals with CRC during 1986-1997, 51.5% of whom were men. In individuals of white ethnicity, the age-adjusted incidence rates for rectosigmoid and left CRC fell over time. In addition, in white men (but not in white women), the age-adjusted incidence rates for right CRC declined. In individuals of African American/black ethnicity, the age-adjusted incidence rates for rectosigmoid and right CRC showed no significant change over time. For all sites, no significant differences in survival were seen over time in whites or blacks.
Conclusions: The decrease in age-adjusted incidence rates over time is consistent with a decrease in CRC burden, especially among whites. However, the lack of improvement in survival over time in whites and blacks indicates that despite advances in screening and treatment, to date, no survival benefit has occurred.