Colorectal cancer outcome inequalities: association between population density, race, and socioeconomic status

Conflicting data exists regarding the influence of population density on colorectal cancer (CRC) outcomes; to better understand this, the present study evaluated outcomes along an urban-rural continuum.

Colorectal patients aged ≥40 years from 1992 to 2002 were identified in the SEER (Surveillance, Epidemiology, and End Results) Registries of the National Cancer Institute in the USA.

A total of 176 011 patients were identified, with median age 71; most lived in populous counties and were white (90%). Patients from large metropolitan counties were more often African-American, and those in rural counties were more likely to be white and have low socioeconomic status (SES). Patients from large metropolitan (>1 million) and rural counties were more likely to have metastatic disease and decreased survival compared to smaller metropolitan counties (<1 million). Late stage of presentation and diminished survival were also associated with African-American race, male sex and lower SES.

Metropolitan counties with populations <1 million had superior CRC outcomes, in part secondary to race and SES.