Study explains why Hispanics are less likely to undergo colorectal cancer screening

A new study finds that Hispanics live in areas with more limited availability of colonoscopies and sigmoidoscopies for colorectal cancer screening. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the study indicates that differences in areas' capacity for providing these procedures may explain why Hispanics are less likely to undergo colorectal cancer screening than non-Hispanic whites. Increasing screening may require efforts to improve the availability of endoscopy in areas with a high ethnic minority population.

Studies have consistently shown that African Americans and Hispanics are less likely than whites to undergo screening for colorectal cancer. While there are several potential reasons for these disparities, one possibility is that areas where African Americans and Hispanics live may have a more limited availability of endoscopies.

Jennifer Haas, MD, MSPH, of Brigham and Women's Hospital and Harvard Medical School in Boston and colleagues examined whether capacity for providing endoscopies in an area where an individual resides is associated with the use of colorectal cancer screening and the stage or extent of patients' disease at diagnosis. The investigators analyzed data on the use of colorectal cancer screening from the National Health Interview Survey (NHIS) as well as data on colorectal cancer stage from both the Surveillance, Epidemiology, and End Results (SEER) Program and Medicare. (NHIS is a nationally representative household survey that collects information about individuals' demographic characteristics, chronic health conditions, health insurance, and health behaviors. SEER compiles incidence and survival data from population-based cancer registries in the United States.) Measurements of counties' capacity for providing endoscopies were derived from Medicare claims.

The investigators' analysis revealed that Hispanics lived in counties with less capacity for providing endoscopies than African Americans or whites (an average of 1,224, 1,569, and 1,628 procedures per 100,000 individuals age 50 and above respectively). Individuals' use of colorectal cancer screening increased modestly as counties' capacity for providing endoscopies increased. For example, as the number of endoscopies per 100,000 residents increased by 750, the odds of being screened increased by 4 percent.

Disparities in screening were diminished after adjusting for an area's capacity for providing endoscopies, its racial and ethnic composition, and the socioeconomic status of its residents. (Adjusting for these factors ensured that they did not account for the finding.) Among individuals with colorectal cancer, those who lived in counties with less capacity for providing endoscopies were marginally less likely to be diagnosed at an early stage of disease, but after adjusting for an area's characteristics, disparities in cancer stage diminished for Hispanics compared with whites but not for African Americans.

These findings suggest "that interventions designed to reduce disparities in the use of colorectal cancer screening or stage at diagnosis should consider not only improving local capacity for screening but also address other characteristics of the areas that may limit the dissemination of information about the importance of colorectal cancer screening," the authors wrote.