Spatial Distribution of Colorectal Cancer Incidence & Late Stage Diagnosis in Houston, Texas (1995-2007)

Survival rates among those diagnosed with colorectal cancer (CRC) are vastly improved when the disease is diagnosed and treated at an early stage [CDC, 2007]. In the United States, racial and social disparities exist in rates of both the incidence and stage at diagnosis of CRC [Ries et al. 2000]. Investigators from the Houston Department of Health and Human Services (HDHHS), the University of Texas School of Public Health (UTSPH), and Washington University are collaborating to identify neighborhoods in Houston, Texas, where disparities in incidence and late stage diagnosis are most pronounced for targeting implementation of local intervention strategies.

Geocoded CRC data (n=14,108 cases) for 1995-2007 were obtained from the population-based Texas Cancer Registry for 592 census tracts encompassing the city of Houston. These data were mapped using Geographic Information System (GIS) software, ArcGIS version 9.3.1. Kernel density estimation was used to identify census tracts with a high burden of CRC incidence and late stage diagnoses.

Population- and age-adjusted cluster analyses were performed using purely spatial Poisson models in SaTScan™ software, version 7. Results indicate that many underserved African American neighborhoods in Houston are at elevated risk of both excess incidence and late-stage diagnosis. Results from this project will allow researchers to target neighborhoods with the greatest disease burden and to implement population-level strategies aimed at reducing this burden in the future.