Investigating the Impact of Geographic Location on Colorectal Cancer Stage at Diagnosis: A National Study of the SEER Cancer Registry.

Background Early detection of colorectal cancer (CRC) is associated with decreased mortality and potential avoidance of chemotherapy. CRC screening rates are lower in rural communities and patient outcomes are poorer. This study examines the extent to which United States' rural residents present at a more advanced stage of CRC compared to nonrural residents. Methods Using the 2010-2014 Surveillance, Epidemiology and End Results Incidence data, 132,277 patients with CRC were stratified using their county of residence and urban influence codes into 5 categories (metro, adjacent micropolitan, nonadjacent micropolitan, small rural, and remote small rural). Logistic regression was used to investigate the relationship between late stage at diagnosis and county-level characteristics including level of rurality, persistent poverty, low education and low employment, and patient characteristics. Results In the adjusted analysis the rate of stage 4 CRC at diagnosis differed across geographic classification, with patients living in remote small rural counties having the highest rate of stage 4 disease (range: 19.2% in nonadjacent micropolitan counties to 22.7% in remote small rural counties). Other factors, such as patient characteristics, insurance status, and regional practice variation were also significantly associated with late-stage CRC diagnosis. Conclusions Geographic residence is associated with the rate of stage 4 disease at presentation. Additional patient factors are associated with stage 4 CRC disease at diagnosis. Cancer outcomes are worse for rural patients, and late stage at diagnosis may partially account for this disparity. These differences have persisted over time and suggest areas for further research, patient engagement, and education.