Invasive Breast Cancer Incidence Among Illinois Women

Abstract

Background Several recent reports have demonstrated a decline in breast cancer incidence in the United States. This study examined the recent temporal trends for breast cancer incidence overall and by age, race/ethnicity, socioeconomic status (SES), and urbanity level in Illinois. Methods Using incidence data from the Illinois State Cancer Registry (ISCR) and population data produced by the U.S. Census Bureau's Population Estimates Program, the annual ageadjusted incidence rates for invasive breast cancer among Illinois women were calculated for the period 1990 – 2004. In addition, Joinpoint regression analyses were performed to quantify the trends at various periods of time. Results Similar to the national trends, a recent decline in breast cancer incidence was observed among Illinois women. The decline for Illinois women, 50 years or older, occurred around 2000 after a steady rise in the 1990s. For these women, a significant upward trend in breast cancer incidence was first observed, with the incidence rate increasing by 2.2 percent yearly from 1990 to 1999 (95 percent CI: 1.8 – 2.5). The incidence peaked in 1999, then a yearly 3.8 percent decline [(-5.9) – (-1.8)] was observed. Analysis by race and ethnicity demonstrated that the decline in breast cancer incidence occurred across racial groups but happened earlier in Hispanic (1997) and African-American women (1998) than in white women (2001). The annual percentage changes in rates were -2.2 [(4.1) – (-0.2)] in African-American women, -5.2 [(-8.6) – (-1.8)] in white women, and -4.4 [(-6.8) – (-2.0)] in Hispanic women, respectively. In addition, similar temporal trends in breast cancer incidence were seen across SES and urbanity levels. A converging trend in breast cancer incidence among racial, SES, and rural-urban groups also was noted. Conclusion The temporal trends for breast cancer incidence among Illinois women were similar to that in the United States. Continuing population-based surveillance in the state of Illinois for breast cancer is warranted in order to provide a comprehensive picture of the burden of breast cancer and to generate new insights about the impact of various interventions.