Racial disparities and socioeconomic status in the incidence of colorectal cancer in Arizona.

Background: The prevalence of racial and socioeconomic disparities in the development of colorectal cancer (CRC) is well known; however, statewide variability exits across the United States. The aim of our study was to determine the overall incidence, socioeconomic and racial disparities in the development of CRC in the state of Arizona.

Methods: We performed a 16-year (1995 to 2011) retrospective review of the Arizona Cancer Registry including all patients with CRC. Patient demographics, stage of CRC disease, and patient outcomes were recorded. The outcome measures were incidence of CRC and the difference in racial and economic characteristics among patients. Logistic regression analysis was performed to identify factors associated with the incidence of CRC.

Results: A total of 40,314 patients with CRC were included of which 16% (n = 6,450) were stage IV. The overall incidence of CRC decreased 17% over the study period. The highest incidence rates were seen in White non-Hispanic and African American populations. Right-sided tumors were more common in White non-Hispanic and African Americans whereas American Indians had higher incidence of rectal tumors and Asian/Pacific Islanders more commonly had left-sided tumors. African Americans had the highest occurrence (42.8%) of more advanced disease (stage III and stage IV). A negative correlation existed between socioeconomic status and the incidence of CRC.

Conclusions: Overall CRC incidence decreased in Arizona by 17%, with greatest decrease rate among, White non-Hispanic and African American populations. Educated patients with higher economic earnings experienced a lower decrease in the incidence of CRC.